During the operation of the vehicle, the driver may notice oil leakage between the engine and the gearbox. Immediately, we note that a similar malfunction appears on different cars, and regardless of what type of motor (,) and gearbox are installed.
In other words, oil leaks at the junction of the transmission and on different cars, when the car is equipped with a manual transmission, a manual transmission, a robotic transmission with one or two clutch discs, an automatic transmission, an automatic transmission with an automatic transmission torque converter, a continuously variable variator, etc.
In any case, if oil drips between the engine and the gearbox, then this is a sign of serious damage. Malfunctions of this kind require immediate diagnosis and quick elimination.
Next, we will talk about why an oil leak may appear between the power unit and the gearbox, as well as what the driver should do if fresh lubricant leaks are visible between the engine and the gearbox, oil is actively running or lubricant on the parts is covered with dust (the leak is insignificant, there is fogging).
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Oil flows between the box and the engine: why is this happening
For a better understanding and quick identification of the problem, let's start with the features of lubricating fluids in gearboxes and internal combustion engines. The fact is that the operating conditions of the transmission and the power unit are significantly different. For this reason, engine oil is poured into the engine, and special transmission oil into the gearbox. For both the engine and the gearbox, lubricant may have.
However, this is where the similarities end. Please note that these fluids differ greatly in their basic properties (viscosity) and chemical additive packages. This is due to the fact that in the engine, lubricant is supplied to loaded units and parts under pressure, and to elements with lower loads it is supplied by spraying.
In parallel, the engine oil is very hot, subject to oxidative processes, etc. In most gearboxes (except for torque converter automatic transmissions), the mating parts are lubricated by splashing lubricant during the rotation of the units, the loads on the parts inside the transmission are much less compared to the internal combustion engine.
Such features of work also determine the overall service life of lubricants in each unit (on average, 10 thousand km for engine oil and 50-80 thousand for transmission oil). We also note that for each unit, the vehicle manufacturer determines individual tolerances for viscosity and other lubrication parameters.
Viscosity of engine or transmission oil is not suitable
Now let's get back to our main problem. It is quite obvious that if a leak between the box and the engine appears immediately after switching from a "thicker" SAE oil to a low-viscosity lubricant (for example, the mineral water was replaced with liquid synthetics), then there is a high probability of a banal non-compliance of the filled material with the recommended parameters.
To put it simply, the use of low-viscosity lubricants in gearboxes and internal combustion engines can lead to leaks. So, what does this information give us? Most importantly, if the oil in the engine or gearbox turns out to be unsuitable, then the leakage can be easily eliminated by replacing the lubricant with the recommended one.
If no other prerequisites for the appearance of leaks have been identified, then it is appropriate to talk about a malfunction. At the same time, the analysis of the oil itself allows you to determine where it flows from, from the box or engine. Let's take a closer look at this.
There is a malfunction in the internal combustion engine or gearbox: how to accurately determine
If the fluids poured into the engine and gearbox meet all the parameters, then the oil leak at the junction of the engine and gearbox is the result of a breakdown of one of these units. Less often, but it is quite possible that problems occur simultaneously in both nodes.
As already mentioned, the grease in the gearbox and the internal combustion engine differs in consistency, color and smell, which allows us to draw some conclusions. For the initial diagnosis, this is very important, since it is possible to more accurately determine which unit is leaking and why. To do this, you need to carefully study the streaks, the color of the oil, dust and dirt on it.
Now let's move on to checking. Immediately, we note that it is usually difficult to determine the exact cause of limited access. In other words, it may not be possible to visually inspect the connection between the engine and the box. In such a situation, the most in a simple way determining where the fluid flows from is.
For this, the level is assessed by the dipstick, a decrease in the indicator will indicate problems with the motor. We add that the gearbox on some cars may also have its own oil dipstick. However, such a check allows you to accurately determine the problem unit when the oil flows out intensively. In this case, you can usually also notice oil stains under the front of the car.
If only drips were found on surfaces and parts at the junction of the transmission and the power unit, then the lubricant level does not always drop much. In such a situation, an additional assessment of the leaking fluid helps.
Motor oil has a lighter reddish-amber hue, it is fluid, its drips conditionally "absorb" dust and dirt. Transmission oil is usually darker and may have a reddish tint (ATF oil). Such a lubricant is thicker, has a characteristic pungent odor, smudges quickly become overgrown with a thick layer of dust, accumulating dirt on its surface in the form of a “fur coat”.
Note that in practice the following method is also often used. Part of the outflowing liquid must be collected in a container into which water was previously poured. When engine oil enters the water, it curls up, retaining the shape of a drop, and then goes down. The transmission fluid does not sink to the bottom, spreading over the surface as a stain.
Oil leaking from engine or gearbox: main causes and repair
The appearance of various leaks at the junction of the gearbox and the engine most often occurs for the following reasons:
- wear or failure of oil seals (for example, rear crankshaft oil seal);
- there were various defects in shafts and seals;
- the appearance and increase of the backlash of the shafts (input shaft, etc.);
- there was a loosening of the fasteners;
- seals and gaskets have lost their properties;
- there was amortization of the stuffing box on the primary shaft of the box;
- the main oil seal may be worn out;
- during repair, the oil seal or gasket is incorrectly installed;
- the geometry or integrity of the pallet is broken;
- oil squeezes out as a result of problems in the crankcase ventilation system;
- there appeared shafts depreciation at the junction of the box and the engine;
- the oil pump or torque converter in the automatic transmission is out of order;
First of all, you need to determine where the oil is flowing from. Then you can proceed to finding the cause and eliminating the malfunction.
Grease is leaking from the engine
Let's start with the powertrain. Typically, leakage often occurs in case of problems with. The specified element usually fails on units with a solid mileage.
The crankshaft oil seal is made of oil resistant rubber. However, during operation, the part loses its elasticity and hardens, and can also be squeezed out as a result of wear of the crankshaft thrust rings. As a result, the oil flows out after warming up the internal combustion engine.
We also note that problems with the rear oil seal of the crankshaft can be caused by a situation when the car is idle for a month or more without starting the power unit. The fact is that during such a downtime, all the grease flows into the crankcase, the seals become dry, and they are deformed or destroyed.
Also, a leak from the internal combustion engine occurs due to the fact that pressure rises in the engine crankcase. The increase in pressure is usually associated with the fact that there is an intensive breakthrough of exhaust gases from the combustion chamber through the worn ones, in addition to the general wear. Another reason may be that the crankcase ventilation system is not working properly due to contamination.
We add that a situation with increased pressure may occur in the checkpoint. If the pressure rises, then the seals, gaskets and seals cannot cope with the load and let the grease out. Lubricant can leak out very actively, which increases the risk of more serious damage to the problem unit. In other words, if the problem is not resolved in a timely manner, then a gearbox overhaul may be necessary.
It is important to understand that oil leaks through the rear oil seal can lead to a rapid decrease in the lubricant level in the crankcase. On manual transmissions and manual transmissions, lubricant from the engine can also get on, causing loss of traction, slipping and jerking during driving.
If the indicated symptoms coincide with those on the dashboard, then it is necessary to urgently check the level of lubricant in the engine. Leaks in the area of \u200b\u200bthe joint between the box and the internal combustion engine will indicate that an urgent need to replace the rear crankshaft oil seal.
As for the crankcase ventilation, then it is necessary to check the slinger valve in the valve cover and assess its condition. If a dark brown or bluish bloom is seen, then this is a sign of problems in the ventilation system. To confirm the diagnosis, you need to unscrew the oil filler cap and then cover the hole with a sheet of clean cardboard.
Then the engine can be started and turned off at idle speed, increasing the speed to 900-1100 rpm. If the cardboard is tightly pressed against the neck, then the ventilation system is working normally, that is, a vacuum is created in the crankcase. If this does not happen, then the pipes and other elements of the system need to be cleaned, purged or replaced.
Oil leaks from the transmission
As mentioned above, the lubricant found during inspection at the junction of the box and the motor can be both engine and gear oil. To begin with, manual transmissions rarely flow in this area, since the oil in them is below the input shaft bearing. Such boxes are more likely to leak grease in the area of \u200b\u200bthe gearbox pan cover gasket or from the breather.
Most often, oil leakage between the engine and the gearbox occurs on cars with automatic transmission. The oil in such boxes is supplied to the mating parts not by splashing, but under the pressure that the oil pump creates. In other words, the pressure inside the automatic transmission is higher.
Often, oil from the automatic gearbox flows out between the automatic transmission and the engine due to a faulty torque converter. As a rule, its malfunction occurs along with the failure of the oil pump. In this situation, an expensive repair or complete replacement of the automatic transmission is required.
We also note that in some cases, lubricant leakage is accompanied by foaming. The appearance of foam in the transmission oil can occur both as a result of overflow or a decrease in the level, and after filling in a lubricant that is not suitable for tolerances and requirements. This is also true for engine oil in an internal combustion engine. If the dipstick shows that the oil level in the engine or gearbox is higher than normal, then you need to remove the excess.
As for the automatic transmission, it is forbidden to add oil to such a box, which differs in properties from the previously filled one. In other words, you can't. To change to other fluids, you must first or the gearbox to remove the remnants of the old grease. After that, a complete box or engine is produced.
Note that in many cases, even a serious repair of the automatic gearbox may not bring the desired results, and the cost of such an operation will be quite high. For this reason, it is optimal to carry out a complete diagnosis of this unit, after which you can decide what will be more profitable, to repair or replace the box with a contract or a new one.
Also, in the process of diagnosing an automatic transmission or other type of gearbox, it should be borne in mind that oil leaks can occur for a number of reasons, which are easily and quickly eliminated. This means that it is not necessary to remove the box right away.
For example, even a loose oil dipstick or an insufficiently tightened drain plug will cause leakage. Also, grease can leak out in the places where various sensors are installed. A common reason is insufficient tightening of these elements, damage to the O-rings in the place of their installation, etc.
If grease leaks out through the sensors, this indicates that the rubber seal is damaged, kinked, or has other defects. The sensor itself can also be destroyed. In this case, the device is replaced with a new one or only the replacement of the sealing element is made (if possible).
The occurrence of malfunctions or noises clearly indicates both breakdowns and problems with the lubricant (insufficient or high level, loss of properties, inadequate lubrication to tolerances and requirements, etc.).
For example, if the transmission hums in neutral, then the bearing on the drive shaft may fail or the transmission oil level has dropped. If the problems are related to the synchronizer clutch or the blocking element, then the noise in the box appears when driving in a certain gear (more often at increased, 3 speed, 4, etc.).
The hum from the box can also appear when the gearbox attachment is weakened. Insufficient squeezing of the clutch pedal or problems with this unit (especially on a car with a single-disk "robot" manual transmission) cause crunching, jerking, jerking, difficult switching. In this case, the parts experience increased loads, after which defects arise, oil appears at the junction of the box with the motor.
If the situation is emergency, that is, a lubricant leak manifests itself on the road and there is no way to put the car for repair, then many drivers try to stop the leak with the help of special additives. As a rule, stop-leak softening sealants contain components that allow elasticity of the sealing elements to be restored.
In other words, it is possible for some time to restore the tightness between the shafts and oil seals. This allows you to get to the place of vehicle repair on your own. So, we strongly do not recommend using such solutions both in the engine and in the gearbox.
First of all, the additive does not remove the wear of the parts, that is, the breakdown itself not only persists, but also progresses. Also, this method is not suitable for heavy leaks. Moreover, the additive has a serious effect on the lubricant and on the parts themselves within the assembly. Otherwise, the addition of an additive deteriorates the basic properties of engine or transmission oil, clogs the lubrication system of the engine and gearbox.
A frequent result is that after disassembling the unit into which such additives were previously poured, complete non-repairability or significant wear of not only initially problematic, but also other structural elements is found.
For this reason, it is better to choose the right lubricant for topping up and use it as needed, rather than buying sealants and additives. Also, auto mechanics and experienced drivers do not recommend switching to a thicker grease after detecting leaks, which is not recommended by the vehicle manufacturer or does not meet the operating conditions of the car.
The same can be said for special oil thickeners. Although this approach in some cases can reduce or eliminate leakage, the lubrication of mating loaded parts also deteriorates. As a result, the wear of engine or gearbox parts is greatly increased.
Let's sum up
A fairly common situation is that the driver may not notice the problem for a long time, especially if the oil seals, gaskets and seals do not leak, but "sweat". In other words, the lubrication level decreases, but gradually. The danger is that the unit is still subject to wear and tear, and sooner or later a strong leak may open. In this case, the gearbox or engine will be without oil in minutes.
For this reason, it is important to pay attention to the occurrence of noise and knocking in the engine and transmission. For gearboxes (especially automatic transmissions), difficult shifting, the appearance of jerks, jerks or delays when shifting gears cannot be ignored. As for oil leaks, it is not worth delaying the repair in this case.
Leaking grease not only contaminates the gearbox and the internal combustion engine, but also gets on other elements in the engine compartment, having a negative effect on them. You should also always remember that a decrease in the lubricant level in the engine or gearbox quickly leads to wear and further damage to these units.
Many motorists were faced with the fact that there was an oil leak between the engine and the gearbox. Of course, as practice shows, everyone goes to a car service to determine the reasons.
But, often, along with existing faults, car service workers attribute those that do not exist. Therefore, it is worth understanding the causes of the breakdown, as well as how to fix it.
Malfunction symptoms
Before proceeding directly to the analysis of the reasons, it is worthwhile to understand that oil drips were formed precisely between the internal combustion engine and the gearbox. The first direct sign is the appearance of an oily stain on the asphalt. Of course, an engine oil leak can be from anywhere. Therefore, it is worth diagnosing the malfunction in more detail.
To determine that oil is leaking from the engine, you must first remove the lubricant level dipstick from the engine and inspect where the oil mark is. According to the technical documentation, for almost all car manufacturers, the lubricant level of the power unit should be located between the maximum and minimum marks, somewhere in the middle.
If the indicator has significantly decreased, then there are either oil leaks on the engine, or fluid goes between the engine and the gearbox.
For a more accurate diagnosis, it is necessary to install the vehicle on a pit or lift and inspect from below. Since many vehicles have engine protection, it must be removed. After dismantling, it will immediately become clear where the oil is leaving the engine. An oil stain will form between the gearbox and the engine and smudges will be visible.
Also, indirect sign It can be assumed that oil spots were found under the car, and the clutch began to work hard, while the gears were changed with difficulty. It can be assumed that the oil squeezed out onto the disc and it is wet. This makes it difficult for the transmission to work.
Causes of the problem and methods of elimination
Why does oil flow? First of all, due to the loss of the sealant's qualities. So, it is worth noting that the lubricant can flow not only from the engine, but also from the gearbox, which is even more dangerous, since it is impossible to establish the real oil level in the transmission on most cars.
To completely make sure that oil flows between the engine and the box, the already installed car in the pit should be disassembled. So, the engine protection is dismantled, and behind it the bolts connecting the gearbox and the internal combustion engine are unscrewed.
It is in the sump of the clutch housing that there is a sufficient amount of oil, and the drive disc will be all wet.
So, the first thing that comes under suspicion is the crankshaft oil seals. These elements can easily fail, even after 100 km of run, since it is impossible to immediately determine their quality. To eliminate the malfunction, you will have to sweat, since in order to replace the crankshaft oil seal, it is often necessary to dismantle the pallet.
Most motorists and engine repairmen do not, though. If we take into account such cars as the Volga, then instead of an oil seal, a stuffing box is installed from which, in fact, the lubricant will leak into the clutch housing.
Worn shafts and seals are also a common cause of malfunction. This applies not only to the engine, but also to the gearbox. The primary shaft is the first to come under suspicion, especially when it is an automatic transmission. In this case, it is necessary to replace the thrust bearings and inspect the housing for wear. If in this case everything is fine, then it is worth replacing the input shaft.
Also, the reason may be - wear of the sealant, which smears most of the joints of metal parts. If it is worn out, the oil can easily squeeze it out and a leak forms.
If the car is filled with inexpensive domestic engine oil, which is not the best specifications, it will flow out with ease, especially when the vehicle is moving. Replacing the sealant can solve the problem of lubricant leakage, but this will require disconnecting the parts where the leak has formed.
Perhaps one of the common reasons why oil leaked out between the engine and the transmission is the loosening of the fastening bolts of the connection in the engine, namely between the pallet and the cylinder block, where the crankshaft is attached. To eliminate the causes of the leak, it is worth tightening the bolts and inspecting the sealing joints.
The wear of the block housing in the crankshaft bearing mounting seat, in this case, it is worth carrying out repair and restoration operations on the housing or choosing a bearing of a larger diameter.
It should be borne in mind that you will have to adjust the case to the part, for this you will need to make a groove for the mounting and installation seat.
Consequences of untimely repairs
Why does oil leave the engine and where it is determined. Now it is worth considering the consequences of untimely repairs. As you know, an engine cannot move without oil, since oil not only has lubricating properties, but also has cooling properties. Therefore, the consequences of a low oil level in the engine will be fatal, especially with a long operation of the power unit. Consider the main consequences:
- Increased wear of the crankshaft and piston group. So, an insufficient oil level can lead to the fact that the output will be significantly higher.
- Increased wear of parts will lead to the appearance in the residual lubricant a large number metal shavings, which will further increase the wear rate of the parts. So, the seals and sealing elements are the first to be subject to wear.
- Also, a low oil level, both in the box and in the engine, leads to the fact that the engine overheats, and accordingly there is a possibility that the engine will overheat and the head of the block will be deformed or deflected.
Output
The main reasons and methods for eliminating leaks between the gearbox and the engine have been identified. Also, it is worth noting that due to the high level of lubricant in the engine and pressure, oil can press on the sealing elements, which will not withstand and depressurization will occur. The consequences of untimely repairs can also be quite severe and lead to a major overhaul of the power unit.
The lubricant used for the engine and transmission is the component that keeps the vehicle running. One of the problems that the owner of the car often faces is the oil leak between the power plant and the gearbox. In this case, it does not matter what kind of fuel the vehicles operate on. This malfunction should be repaired immediately, as it is a sign of serious damage.
Use of oils for engine and transmission
Mineral, synthetic or semi-synthetic fluid can be used for the engine and transmission. The synthetic version of the fuel is popular. It facilitates starting the power unit. At low temperatures, this oil:
- does not thicken;
- optimum fluidity is maintained.
Mobil 1 transmission fluid
Mobil 1 has these qualities. Even at -40 ° C it does not lose its properties.
On most cars, the engine oil changes at 10,000 km, the transmission fluid must be changed at 50,000 or 60,000 km.
Thus, engine and transmission fluids differ in their performance characteristics. The vehicle system needs to be checked if there are leaks between the engine and gearbox. Adding, for example, synthetic oil to mineral oil leads to smudges. In this case, replace the filled oil, add what was previously.
Causes of oil leakage between the box and the engine on a car
There are oil seals in the engine compartment. The main function of the oil seal is to prevent leaks and fuel on the moving parts of the power plant, as well as the gearbox. To replace this consumable item, it is worth draining the fuel, removing all fasteners. Armed with a screwdriver, the oil seal is dismantled.
Every 10,000 km, the car must be sent for diagnostics, where workers can check the condition of the breather. If this element is clogged, oil leaks from the gearbox, engine due to the fact that the necessary ventilation is not carried out. This results in an increase in pressure in the vehicle system. This leads to the fact that the oil seals are squeezed out of the standard place, as a result, the driver is faced with such a problem as oil leakage.
If oil leaks at an automatic transmission, you must:
- check the working ability of the torque converter;
- condition of the oil pump.
Ignoring this malfunction will lead to high financial costs. In some cases, installing a new box will cost less than repairing an automatic transmission.
Another reason why oil leaked out of the box is an incorrectly installed dipstick. This item allows you to accurately determine the oil level. In the event that it does not close the channel well, there is a risk that a leak will be noted.
Thus, there are several reasons why oil flows from the gearbox. Firstly, it is the wear of the oil seals, sealing elements. This is often the result of natural wear and tear. Leads to wear of the oil seals and used low quality oil. In this case, the consumable must be replaced. Secondly, loose fasteners, bolts. Their adjustment is necessary. You also need to check the breather. All of these are common reasons that are easy to fix on your own. In this case, you need to determine the site of the leak. You can find smudges under the car.
Oil Leak Locations and Troubleshooting
If oil leaks from the gearbox, the vehicle will malfunction. To get rid of the reasons why there is an oil leak between the engine and the gearbox, it is advisable to drive vehicles into the inspection pit. Thanks to this, it is possible to accurately determine the place from which the fuel flows.
It should be noted that the detection of oily droplets under the vehicle is not only a consequence of the transmission leaking, but also the result of a broken steering rack.
It is possible to eliminate the reason why oil is dripping between the engine and the gearbox by replacing the gearbox. The mechanical box is distinguished by its maintainability; not every service center undertakes to repair automatic boxes.
How to fix oil leaks? In order to prevent the occurrence of drips, it is advisable to ensure the tightness of the lubrication complexes. Thanks to this, the transmission system will function when high pressure... On a number of versions of a car, to replace the oil seals, you should dismantle the box from its regular place. This process requires carefulness. That is why it should be entrusted to specialized service workers.
When oil is leaking from the gearbox, a grinding sound may occur in parallel. The reason for the grinding is often the lack of the amount of fuel poured. The lower the level of the filled oil, the higher the risk that the components of the speed box will fail prematurely. In addition, a low engine oil level will cause the engine to overheat, contributing to premature cylinder head failure.
The amount of oil for the vehicle system must comply with the standards set by the vehicle manufacturer. If there is an excess amount of liquid, it is squeezed out through the sealing elements. It is advisable to replace the gearbox sealing elements if they cannot withstand the oil pressure.
Oil leakage from the gearbox is the result of an aggressive driving style. If oil flows between the engine and the gearbox, then this problem should not be postponed. Eliminating the problem early helps to minimize the risk of serious vehicle problems.
Thus, one of the common vehicle breakdowns is oil leakage between the high-speed gearbox and the powertrain. Timely car maintenance will prevent the occurrence of a leak from the gearbox. For each version of the car, you should use the appropriate quality oil. Defective consumables that are causing leaks must be replaced.
Every driver who takes care of his car develops a good habit over time: before going on a trip, you need to check for any traces of oil or antifreeze leaks under the car. A good solution would be the following method - in the evening, before parking the car, place a clean piece of cardboard under the engine and gearbox (for example, from a box) and then in the morning you can more accurately localize the problem.
If you see something suspicious, then try to find the cause of the oil leak between the gearbox and the engine and eliminate it - at a specialized service station or on your own. One of the most common oil leaks is the connection between the gearbox and the engine. Well, if you keep the engine compartment clean, then it will be easier to find the cause of the loss of lubricant. Otherwise, before diagnostics, you will have to wash everything clean in order to accurately localize the leak.
Features of the lubrication system of the engine and gearbox
The engine and gearbox are lubricated with oils with different chemical composition... An experienced driver or mechanic will be able to immediately determine, by smell or color, which unit is losing lubricant. The engine is equipped with a forced oil supply system to rubbing components and assemblies.
In a manual transmission, oil is supplied to the friction points by "splashing" from the rotating parts. In automatic transmissions, the supply takes place using an oil pump. In a manual transmission, oil leaks are rare when the machine is stationary. The design feature is such that the oil level is less than the bearing on the input shaft. Therefore, on this type of box, losses occur during movement.
The oil change times for these units are different: the engine oil is changed every 8-15 thousand kilometers, and the transmission oil is replaced after 50-70 thousand.
The amount of oil added to the engine or transmission must comply with the manufacturer's guidelines. With oil starvation, rubbing parts wear out faster and their service life is significantly reduced.
If the oil is poured in excess, then the banal squeezing out of the excess through the weak points is possible. It is necessary to constantly monitor the level of lubricating fluids. Make a habit - before starting the car, check the oil level in the engine, box, coolant expansion tank, and the amount of brake fluid. Timely treatment will be much cheaper than a major repair.
Possible causes of oil leakage between the gearbox and the engine
As soon as you notice the first signs of an oil leak, you need to immediately look for the place of failure. It is impossible to delay the solution of this problem. You don't want to stand somewhere in the middle of the field and return home in a tow truck, do you? The most convenient way to determine the location of the oil leak between the box and the engine is on a lift or a pit. Liquid drops are definitely a flaw and you need to get rid of it.
It is unlikely that it will be possible to instantly identify a broken unit - the lack of direct access to vulnerable nodes makes this difficult task difficult. Most often, the problem is in the gearbox and, most likely, it will have to be dismantled for accurate diagnosis and elimination of the problem.
Each car has its own characteristics, but there are some general principles for diagnosing and eliminating breakdowns. First of all, it is necessary to decide what type of oil flows out - oil from the engine or from the gearbox? This can be determined by the smell and type of contamination. The size of the stain can determine the severity of the problem and the amount of oil lost.
In used cars, the main oil seal of the engine first begins to leak. Increased axial movement of the crankshaft causes the oil seal to be pushed out and leaks. Worn oil-resistant gland rubber can no longer contain oil, which has warmed up to a fluid state. With a clogged crankcase ventilation system, the pressure in the system rises, and excess oil leaves through weak points.
The transmission also has its own ventilation system: through a special breather, the expanded hot air leaves the system. If it is clogged, then excessive pressure is created and the oil is also squeezed out. There is only one real option for eliminating the oil seal leak - replacement. And if you change one of the oil seals, it is better to immediately replace the second one, so as not to remove the box twice. Immediately it is worth checking the shaft play, the condition of its seat, and bearing wear.
Causes of oil leakage that can be eliminated without removing the box:
- the drain nut is loose;
- loose installation of the measuring probe (if provided in the transmission design);
- the sensors are poorly wrapped.
If you didn’t manage to get off with "little blood" and the oil leak between the box and the engine continues, get ready for more serious and expensive repairs. By the way, count with the master - maybe replacing the box will come out cheaper than major repairs.
Reasons for removing the box from the car:
- violation of the tightness of gaskets or seals;
- wear of the main oil seal;
- wear of the gearbox input shaft oil seal;
- incorrect installation of oil seals;
- violation of the geometry of the pallet - a hit or bent pallet tears the gasket;
- a clogged crankcase ventilation system can create excess pressure and squeeze out oil;
- wear of the shafts that connect the engine and the box;
- gearbox input shaft play;
- breakdown of the torque converter or oil supply pump on automatic transmissions.
Oil additives
Some drivers, seeing the oil leak between the box and the engine, immediately go to the auto chemistry store for the magic one. The additives contain special substances that restore the elasticity of the seals. This property ensures the restoration of tight contact of the stuffing box with the shafts and can eliminate oil leakage for a while. Yes, an additive can help, but only for a while and only with a slight system leak.
The wear of the part will not go anywhere, and therefore the breakdown remains, and the chance to get to a more expensive repair or replacement of the unit increases significantly. The use of oil thickeners is not recommended. They can eliminate the leak, but at the same time worsen the lubrication of the components, which is fraught with increased wear of the engine or gearbox. If you do decide to use an additive, choose an emollient sealant.
Let's summarize:
- traces of oil on the garage floor - a mandatory reason for inspecting the engine, gearbox and joints;
- the weak point of used cars - oil seals, most likely, their service life has come to an end;
- be sure to check the ventilation system of the engine and gearbox;
- the additive will not help - most likely, your car will have to be treated more seriously.
As a rule, the driver learns that oil is leaking from the gearbox when he finds characteristic fluid drips on the ground under his car. Naturally, an ATF leak is a sign of a breakdown, so in order to find out why the oil is leaking from the gearbox, you need to pay special attention to finding out the cause.
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Why is oil leaking from the gearbox?
Having found the first signs of oil leakage from the gearbox, or between the engine and the gearbox, you should quickly find out the defective place. An oil puddle can be seen under the hood of your car or under the bottom, but for this it will be more convenient to drive the car onto an overpass. In any case, if liquid drips, this flaw must be got rid of.
Sometimes it is very difficult for a driver, especially if he has been driving recently, to identify the very defective place. This is mainly due to the fact that the process of finding fluid leaks from the box or between the engine and the box can be complicated by a number of circumstances, as well as limited access to most of the weak points of the box. Based on practice, it can be assumed for what reasons the liquid is leaking or dripping:
- unsuitability of oil seals;
- wear of shafts, which, in one way or another, are associated with the sealing elements;
- non-standard backlash of the automatic transmission input shaft;
- the need to replace the sealing layer;
- loosening of the bolts connecting the box elements;
- unsuitability of the seal.
Topping up fluid in automatic transmission
If you notice that the seals on your automatic transmission are really old, but dry, then it is better to replace them immediately so that they do not become the next cause of leakage. If the leakage problem is the seals, then they should also be replaced.
To replace the oil seals of the drive shafts of the wheels, you need to proceed in stages:
- First you need to drain all the oil from the box.
- Then it is necessary to rinse the box with kerosene or diesel fuel so that the remains of the old fluid do not remain on the walls.
- Remove the hub bearing nut, and several bolts securing the ball joint.
- Remove the axle shaft.
- Remove the oil seal using an awl or screwdriver.
Why does oil flow between gearbox and engine?
If oil leaks or drips between the engine and the gearbox, you need to find the defect as soon as possible in order to eliminate it. If the defect occurred due to the fact that the crankshaft oil seal or gearbox input shaft failed, then we can assume that you are lucky - then the repair will cost a minimum.
However, things can be much worse, because if ATF drips or flows between the engine and the gearbox, this indicates a breakdown of the torque converter - then the car owner will have to fork out for repairs. It is worth noting that such problems are more common in Japanese or European cars, much less often in cars assembled overseas.
Oil leak from gearbox
Attention! Untimely solution of the problem with oil leakage between the gearbox and the engine can lead to the complete failure of your gearbox.
For what reasons does the oil foam in the gearbox?
Even if all components of the vehicle are working properly, ATF can foam. This defect will not bring big problems to the car owner, but any driver, in order to fix the malfunction, should know why this is happening. Transmission fluid often foams in automatic transmissions for several reasons, due to the wrong ATF level or mismatch of the oil manufacturers.
- When it comes to liquid level, a high or low level (compared to the mark on the dipstick) is the most common reason for liquid foaming. If you have poured too much ATF, it is advisable to drain the excess immediately. This is especially true for the owners of German cars - Audi, Mercedes, BMW, Volkswagen - these cars are the most sensitive to problems with automatic transmission oil. The lowered level is usually caused by a leak, which may be due to the inadequacy of the gasket - replacing it will help solve the problem.
- As for the oil producers. It is strongly not recommended to add oil from a new manufacturer to the box of your car if the old one remains in it. Otherwise, foamed oil in the gearbox is provided to you. If you decide to switch to a fluid from another manufacturer, then before changing the oil, the box must be flushed from the remnants of the old transmission fluid.
Draining fluid from automatic transmission
Why is there noise at the checkpoint?
As practice shows, the noise coming from the gearbox can appear when the car is moving both in neutral gear and at speed, and in both cases the noise can be different. One way or another, the noise in the checkpoint indicates a malfunction of the box.
- If the gearbox starts to make noise while driving at neutral speed, then this is due either to a malfunction of the drive shaft bearing, or to a low ATF level in the gearbox.
- If noise appears in a certain gear (as a rule, starting from the third), then this indicates a failure of the blocking component or the synchronizer clutch.
- Also, noise may appear when loosening the threads of your gearbox mounting.
- Do not forget about the ATF level - its lack in some cases also provokes outside noise.
Gear box
Important! incomplete depressing of the clutch pedal also leads to the appearance of noise or rattling in the box.
Which is better for noise reduction: additive or oil?
Some drivers, having heard the noise in the gearbox, do not go to a specialist at the station, but to an auto store to buy special additives.
You need to understand that adding additives to ATF (whether it be an engine or a gearbox) will actually help to temporarily eliminate noise, but the additive can also negatively affect the condition of your gearbox or engine as a whole. If high-quality ATF is filled in, then the additive is definitely there. Moreover, its level is properly balanced, and adding a new component to the box can upset this balance. If, by adding an additive, the transmission fluid loses some of its properties, this is only half the trouble. It is much worse if, due to the additive, the lubrication system of the engine or gearbox becomes clogged.
It is better not to experiment, but to pour into the box only the ATF that the manufacturer advises, and refrain from using additives.
Video "Renault Symbol Gearbox Repair"
In this video you will learn how to repair a gearbox in a Renault Symbol car.
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