When changing the oil, car owners often find themselves unable to get rid of oil residues accumulated on the walls of components and mechanisms. However, as a rule, it is not recommended to mix new motor oil with old one. A flushing liquid was developed to eliminate oil residues. It not only allows you to remove oil residues, but also stabilizes the acidic environment formed during the operation of the vehicle when using old lubricant.
However, flushing is unable to remove heavy soiling and solid residues. In this situation, you will have to disassemble the automatic transmission and clean the mechanisms yourself.
Why wash the box?
Flushing an automatic transmission before changing the oil is a rare procedure for service stations today.
The reason is not that it is expensive. It all lies in the ignorance of both car owners and service specialists. Most servicemen are not able to understand the intricacies and features of modern automatic transmissions.
In recent years, the main trend in car construction has been fuel economy, without sacrificing power and dynamics. Modern gearboxes already have 6, 8 or more steps, and shift much faster. To make the operation of the car even more economical, the torque converter has an additional clutch with partial high-frequency blocking - it improves acceleration dynamics, while the car does not consume a lot of fuel. But there are also disadvantages that are usually forgotten.
ATP liquid after 100 thousand mileage - it’s scary to imagine what kind of “mayonnaise” remains inside
The main disadvantage is the accumulation of wear products in the transmission fluid. These are small metal shavings, rubber dust, a product of the breakdown of torque converter clutches and other clutches in the box. The standard filter cleans oil from production, but not completely. A significant portion of chips and other particles circulates in the oil channels. The valves in the solenoids also wear out, since the latter are forced to work more often than on traditional 5-speed automatic transmissions. The situation is aggravated by the fact that manufacturers are switching gearboxes to oil with low viscosity - it protects parts less well from wear. And what do we see in the service book? The fluid is filled for the entire life of the car...
This box has already “arrived” at the capital
All this leads to the fact that most boxes are repaired after 60 thousand kilometers. And it doesn’t matter who the manufacturer of the automatic transmission is - the Japanese Aisin or the French AL4. But our car owners have long proven that even unsuccessful automatic transmission models can “run” 250 thousand kilometers. The secret is simple: timely maintenance and competent diagnostics.
Most service stations now do a partial replacement: drain half the waste volume and add fresh ATF in equal quantities. But there is one “but”: with such maintenance, most of the chips and dust remain inside, reducing the life of the box.
When a partial replacement does not help, car owners turn to automatic transmission flushing when changing the oil, which allows:
- reduce the likelihood of serious breakdowns of the automatic transmission;
- remove minor defects in the operation of the automatic transmission (vibrations, kicks) if they are caused by dirty channels and cavities.
Al4 automatic transmission valve body repair
Annual scheduled repairs must take place in a service station. Maintenance involves removing the Al4 valve body, washing, replacing faulty parts, completely replacing the lubricating fluid (Mobil ATF LT 71141) and the filter device (No. 144010).
The filter device, with proper operation, timely topping up and changing the lubricant, according to experienced mechanics, survives a period of 80,000 kilometers and can remain clean.
Removal
Before removing the Al4 automatic transmission valve body, you need to drive the vehicle for 10 minutes. Then drive into a pit. The first steps will be no different from those for replacing the lubricant.
- Unscrew the drain plug on the automatic transmission pan.
- Place a container for lubricating fluid, which will flow under pressure from the hole formed.
- Wait until the oil stops dripping.
- Unscrew the automatic transmission pan. First clean it of metal shavings and leave to dry.
- Disconnect the terminals that the car owner can see. When removing the rod and ratchet with a finger, you need to remember what position it was in or mark it by scratching a line with a metal core. In the correct position it will always be motionless. If there is play, then it will need to be reinstalled when the car owner reassembles the automatic transmission valve body.
- Unscrew the bolts that hold the valve body with the Al4 automatic transmission.
- Pull out the hydraulic plate.
Diagnostics and repair of Mazda 6 automatic transmission
Flushing
After the hydraulic unit has been pulled out, it must be completely disassembled and washed. To do this, the car owner can use various cleaning products. Clean the fine filter if it is dirty. After washing, you need to assemble the hydraulic unit. The bolts are tightened from the middle to the edges. Tighten to a torque of 0.8 daNm.
It should be washed in white spirit. If after the first cleaning the solution is dirty, you need to fill in another one and rinse the hydraulic unit again. Since inside the holes for the valves there may be fumes and wear residues of parts that enter there along with the hydraulic fluid during operation of the Al4 automatic transmission.
After flushing, it will be necessary to replace the solenoids and valves. Then adjust them. Carry out the replacement carefully and install everything in its place so that the automatic transmission does not slow down when changing gears after repair.
Solenoids
New solenoids in the al4 automatic transmission are changed in pairs. It is advisable to also change the old ones in pairs. After replacement, it will be necessary to carry out adjustment with a special program. How to do this using the adjustment utility will be described in a special block.
The temperature sensor will need to be replaced. If it is faulty, the vehicle may go into emergency mode and will not start.
Reasons for automatic transmission going into emergency mode and ways to reset the error
valves
It is advisable to replace all solenoid valves in Al4 automatic transmissions. Since one worn valve can lead to an imbalance in pressure causing new ones to fail.
The valve pistons also need to be cleaned in white spirit until shiny. They must fit tightly to the walls of the channel and at the same time fall into it under their own weight.
Cleaning Frequency
There have been no official studies regarding automatic transmission flushing, so it is difficult to say how often an automatic transmission should be flushed. Mechanics, based on personal experience, recommend performing the procedure before each ATP fluid replacement (that is, every 35-70 thousand kilometers).
Removed tray for washing
Sometimes it is worth performing non-scheduled flushing if there are:
- kicks when switching, which were not there before.
- jerking and jerking during acceleration;
- vibrations and other signs of unstable transmission operation.
Symptoms of a problem
A popular reason for torque converter failure and needing repair is overload from aggressive acceleration and overheating. The clutches are the first to suffer. They wear into dust and burn from a lack of oil, which leads to vibrations and shocks when the lock is connected.
The reactor overrunning clutch also experiences heavy loads. The splines of the aluminum body wear out, causing the hardened holder to slip. Aluminum dust from abrasion of the housing can be seen in the pan when changing the oil. A clutch malfunction appears when R or D is turned on, if the motor becomes very tense or stalls.
A noticeable kick or vibration in downshifts may indicate there is not enough pressure under the piston to fully compress the clutches. Cause: broken seat of the input shaft. Intensifies during repairs.
Oil contamination on an old Mercedes 30,000 km after replacement indicates that it is time to change your driving style or torque converter locking. Without special equipment, it will not be possible to determine the internal state of the donut. For repairs, you will need different machines and an experienced technician who will not forget to check all the weak points in the Mercedes unit.
Advantages and disadvantages
Complete flushing will allow maximum removal of gear and clutch wear product from the channels and system. In addition, completely fresh oil is poured in, and not mixed with old oil, as with a partial replacement. And finally, flushing the automatic transmission, in addition to removing dirt, allows you to preserve the oil seals and seals of the valve body. This will extend the life of the hydraulic part and make the box work more adequately, without jerking and kicking.
There are no downsides if you do everything yourself. At the service station, the operation will cost a certain amount - this is the only negative.
Popular brands:
Audi S8, BMW 7-Series, Kia Rio
Standard method
In this case, the automatic transmission will be flushed with an oil change. What to do:
- .Drain the old oil. It is advisable to warm up the box (it is enough to drive 2-3 kilometers). The oil becomes more liquid and drains much faster.
- Find the drain hole on the bottom of the crankcase and unscrew the drain plug - this is a shortened bolt with a recessed head. Wait. until the liquid stops dripping.
- Remove the automatic transmission pan. Caution: Remember that the oil is still hot. The tray should be thoroughly washed from the outside as well as from the inside. It is recommended to degrease and wipe its surface dry.
- To flush the automatic transmission, prepare a pump, hoses of sufficient length and a suitable container. Connect the hoses to the cooling system of the box, start the engine. Washing takes from ten minutes to half an hour, depending on the degree of contamination of the box.
- After cleaning is completed, replace the oil filter and crankcase gasket. The filter is most often located at the bottom (near the valve) and is easily installed after removing the crankcase. The filter is attached to different automatic transmissions in different ways - from latches to bolt-on mounts. It is better to install the gasket on the sealant.
- Reinstall the tray.
- Add fresh oil.
Filling with new ATP fluid
Important! You need to pour exactly as much oil into the box as was drained before. Remember that both underfilling and overfilling are harmful to automatic transmissions.
- Check the level on the dipstick - it should be between minimum and maximum.
- Start and warm up the engine, take a short drive;
- Check the oil level, add if necessary. Also check for any leaks around the box. If they are not there, the replacement can be considered successful.
You can work according to a different scheme. Instead of oil, regular diesel fuel is poured into the automatic transmission. Then start the engine, let it run for 10–15 minutes and drain the liquid. If clean diesel fuel comes out, stop washing. If it is dirty, then cleaning with diesel fuel continues again with a new portion being poured. But experts do not recommend using dimexide - it is very aggressive towards friction clutches.
Washing the automatic transmission without removing it from the machine
This procedure is carried out using a special device. Standard list of work carried out by service station employees:
- First, the used old oil is drained. In order for the maximum amount of used fluid to flow out, the automatic transmission pan is removed and the drain plug is unscrewed.
- After draining the liquid, all parts are installed in their original places.
- A device filled with new transmission oil is connected.
- The engine starts.
- The motor runs for at least 15 minutes.
- At this time, oil under pressure passes through all channels of the automatic transmission hydraulic system.
- The ATF oil from the automatic transmission is drained again.
- The worn oil filter is removed and a new filter element is installed in its place.
- The automatic transmission pan gasket is being replaced.
- Fresh transmission oil is added.
Advanced cleaning
Sometimes it is not possible to wash all the dirt out of the automatic transmission. So, you can use a complicated method of completely washing the automatic transmission with your own hands. But the disadvantage of this technique is the need to dismantle the unit. You need to disassemble the box and wash each element. How the work is done:
- drain the old oil from the box;
- The automatic transmission is dismantled, disassembled, and each part is washed separately using washing chemicals;
- internal channels are purged with compressed air;
- The box is put back together and fresh oil is added.
Important! When assembling the box, new seals and gaskets must be installed.
After such an operation, you need to run the car in a gentle mode for a week. Despite the difficulties associated with the need to completely disassemble the automatic transmission, this method is more effective - using it, you can completely clean the insides of the transmission from wear products.
What you need to prepare for washing the automatic transmission
This event is best carried out in specialized workshops. Most service companies are equipped with special washing devices, with the help of which the unit is washed at the proper professional level. If during diagnostics it turns out that it is necessary to disassemble the automatic transmission and change some parts and components, the box is rebuilt, all its elements are washed in gasoline, and the channels are purged with compressed air.
If you decide to flush the automatic transmission yourself, you need to create the conditions and acquire consumables, auxiliary tools, and accessories:
- Transmission fluid in double volume (the first portion of ATP oil will be used for flushing the unit, the second - for refueling, respectively).
- Adjustable wrenches, sockets, polygons, gasoline, screwdrivers, pump.
- Bucket or basin for waste material.
- Cotton rags.
- Observation deck, overpass.
Pallet
It happens that a layer of dirt accumulates in the automatic transmission crankcase, which cannot be washed without removal. It is secured differently on different cars, but the principle is the same - unscrew the bolts along the contour. You can clean it with whatever you have at hand - gasoline, carburetor cleaning fluid and even dimexide (this is where it is safe to use). The liquid is simply poured into the crankcase, given time for the dirt to dissolve and drained. Wipe dry with a rag and put the tray in place.
Do-it-yourself crankcase cleaning
Often car owners, when washing the box themselves, use gasoline. But if the contamination is severe (and it happens that almost black oil drains from the crankcase), gasoline does not help. You can try a product from household stores - Shumanit. The product corrodes any contaminants. You can also use diesel fuel, kerosene, five-minute flush and other similar liquids as a liquid.
How to repair Mercedes torque converters
Repairing a Mercedes torque converter is expensive due to the complex design of the unit with a large number of consumables. The bagel is restored during repair of the entire automatic transmission or separately. Specialized Mercedes transmission repair services accept units from different regions of the Russian Federation and CIS countries through a delivery service.
After removing the Mercedes torque converter from the automatic transmission or sending it for repair, the technician inspects the body for cracks, damage to the journal, and the quality of welding of the seam. Then he drains the old slurry and saws the body on a lathe.
The repairman begins the repair with troubleshooting:
- checks the wear of the bushing between the pump wheel and the locking piston;
- inspects the piston for scoring;
- assesses the degree of wear of steel and friction discs;
- checks the damper springs for cracks;
- inspects the integrity of the pump and turbine wheel blades;
- checks the condition of the aluminum splines of the reactor and the stroke of the coupling;
- assesses the condition of bearings;
- throws out all rubber seals and other consumables.
At the next stage of repair, the parts of the Mercedes torque converter are washed with solvents to remove dirty slurry and blown with compressed air. The technician re-inspects the clean parts. Damaged ones are replaced with new ones or restored. Metal discs and piston are ground on a machine.
The weak points of the Mercedes torque converter are tuned during repairs:
- install additional bushings to protect against pressure reduction through the shaft hole;
- return springs are installed to prevent idle slipping of the clutches;
- fix the antennae of the turbine wheel blades in a toric disk, which can become loose over time;
- Pins are inserted at the coupling points between the reactor vessel and the cage to prevent rotation of the cage in the future.
At the next stage of torque converter repair, the master grinds the housing for a new clutch, trying to cut off a minimum layer of metal. This is necessary for the free connection of the housing halves with a minimum gap.
The Mercedes torque converter is assembled with new seals, friction discs and restored parts. The body is welded on a special platform, controlling the alignment with an accuracy of one hundredth of a mm and the gap between the top and bottom covers. The repair ends with checking for leaks, axial runout and balancing on the machine.
On worn-out Mercedes, repairing the torque converter is too expensive, requires replacing many parts, or is completely impossible. In such cases, repairmen offer to replace the unit with a new, refurbished or contract one.
Flushing the hydraulic unit
Cleaning the automatic transmission valve body is not as scary as they write or talk about it. It is necessary to unscrew the valve body mounting bolts and carefully remove the part downwards. The solenoids can be cleaned using carburetor cleaner.
Cleaning the valve body
Small parts are also washed with carb cleaner. But it is better to wash the stove with gasoline, kerosene or diesel fuel - soak it overnight, rinse and dry.
Let's sum it up
As you can see, the hydrodynamic transformer of the gas turbine engine is an important device, being the automatic transmission clutch. However, taking into account the loads on this element, it can fail much earlier than the automatic transmission itself.
For this reason, taking into account the high cost of a new gas turbine engine, a faulty device can often be restored through repairs
Washing the automatic transmission filter
There are two types of filters for automatic transmissions:
- Reusable with fine mesh element. Such filters can be saved by washing.
- Paper or synthetic filters. They are not washed, but replaced with new ones.
The filter is usually cleaned when flushing the automatic transmission housing. You can do this yourself - the first step is to drain the old oil, remove the crankcase and dismantle the filter.
Cleaning the filter
The body of the latter may be covered in plaque or dirt. Carburetor cleaning fluid can easily remove this dirt. Once the housing is clean, you can disassemble the filter. Depending on how dirty it is, the mesh is washed with the same carb cleaner or gasoline. Wash until the mesh is visible. When its cells are clearly visible, the structure can be assembled.
What is a valve body in an automatic transmission?
The hydraulic plate is called the “brains” of automatic transmissions, not only for the external resemblance of the complex channels to the convolutions of the brain. Before the advent of control electronics in the 1980s, the valve body decided which automatic transmission unit needed to be connected to operation. Now the valve plate is controlled by the computer, maintains pressure in the system and distributes fluid flows from the oil pump to the actuators: clutch packs and torque converter lock-up (GDT). The hydraulic unit includes:
- a metal plate with a labyrinth of channels through which oil passes;
- solenoids;
- pressure regulators;
- spool valves;
- sensors;
- filters;
- hydraulic accumulators;
- wiring;
- separator plate, seals.
ZF simultaneously made the evolution of the machines and created a new problem for repair by introducing an electronic board into the design of the valve body.
Operating principle of the automatic transmission valve body
The automatic transmission valve body maintains pressure in the system using a group of valves:
- solenoids open and close channels for the passage of fluid to the clutches and gas turbine engine;
- the regulators create the linear pressure of the main line, necessary for lubrication and cooling of the box, as well as for locking the clutches. The pressure increases when the car accelerates and reverse gear is engaged, and decreases when braking;
- synchronizers prevent shocks when changing gears by regulating the sequence of step transitions;
- adjustment valves change the pressure value to improve the operational parameters of the automatic transmission;
- hydraulic accumulators soften shocks in the box, maintaining the inertia of compression of the clutches due to the tension of the springs.
The signal to open the solenoids comes from the ECU. The position of other valves depends on spring tension and fluid pressure. The pressure inside the valve body varies depending on the throttle position: with increased torque, the linear pressure increases, which prevents slipping.
Flushing the automatic transmission torque converter
It is almost impossible to do this procedure on your own. Flushing the torque converter is only possible if you cut the donut. Without opening, washing is ineffective and will not have any noticeable effect.
Opening the torque converter
If the housing is sawn, then all the elements of the torque converter immediately become accessible - you can visually assess the scale of the problem. After troubleshooting, cleaning begins. Thoroughly wash the turbine blades and elements in the clutch mechanism.
The cleaning procedure is simple - the part is immersed in a container with a high concentration cleaning solution and the carbon deposits are washed off manually. After cleaning, all dismantled elements are installed back, and the torque converter housing is welded. Next, the system is checked for leaks.
Torque converter lock-up clutch control
The blocking is controlled by finely tuned TCC solenoids using the EGS signal:
- The electronic unit analyzes information from the gas pedal position sensors, throttle opening degree, etc.
- Transmits a PWM pulse to the TCC to convert the current into the corresponding pressure.
- Pressure from the solenoid flows through the input shaft into the cavity behind the locking piston.
- Between the housing and the clutches the pressure is released, and between the turbine and the clutches it increases.
- The discs are pressed against the body with the required clearance.
- The locking is turned off as the speed decreases or when the oil heats up above 140℃. The oil is “pumped out” into the solenoid until the next signal. If the fluid is contaminated with friction dust, the solenoid valve quickly becomes clogged and requires repair.
The computer does not know how to “read” the degree of wear of the clutch, and continues to operate the lock in normal mode even if the disk is completely worn out. The valve body and radiator become clogged. Rubber bands and seals are leaking. The Mercedes transmission is increasingly overheating, requiring urgent repairs.
In the Mercedes 722.9 automatic transmission, torque converter lock-up slip is activated already in first gear, which is essentially a controlled friction clutch. But this solution leads to oil contamination after 60,000 km, and the donut comes in for repair after 100 - 150,000 km.
Flushing the transmission radiator
The automatic transmission gets very hot during operation, and therefore it has a cooling system with a separate heat exchanger. If the latter is not dirty, it will cope with heat removal without any problems. But as soon as a layer of dirt accumulates in the channels, the box overheats.
Cleaning the heat exchanger inside
The radiator is washed together with the gearbox before changing the oil. The most effective method is a mixture of alcohol and aqueous solvents. The service station has a washing stand for this purpose. But in a garage you can use a circulation pump yourself. How it all happens:
- remove the automatic transmission oil pipes;
- a hose coming from the pump is connected to the inlet pipe;
- the second pipe is inserted into a container suitable for washing;
- the receiving container is filled with solvent;
- The liquid is pumped into the radiator through the “return” hose (that is, it should pour out from the supply part).
- turn on the pump for up to 15 minutes.
Next, the solvent is drained. If it turns out to be very dirty, the procedure is repeated. If instead of a solvent you use a cleaning agent in aerosol cans, cleaning is carried out according to the same scheme - from supply to return. You need to pour in so much chemical until a clean solution comes out of the return part.
When washing is completed, be sure to dry the heat exchanger - this can be conveniently done with an air compressor. Next, about a liter of working fluid is poured into the automatic transmission radiator, checking it for throughput. If the liquid does not come out well, such a radiator needs to be changed - no amount of cleaning will help it.
External plaque
Important! The radiator must be clean not only inside, but also outside. We carefully wash away all the dust under low pressure of water so as not to damage the honeycombs.
How to flush the automatic transmission yourself
If the car owner does not know how to flush the automatic transmission on his own, then the following instructions will help him with this.
The usual procedure is carried out by draining the used oil and adding new oil, starting the engine and repeating the process using the displacement method. This method is used when completely replacing the lubricant. In this case, the box is not dismantled.
You can wash the box this way by following the steps below:
- Start the engine and warm up the vehicle's automatic transmission to operating temperature.
- Drive onto the overpass.
- Stop the engine and drain the used oil into a special container.
- Disassemble the pan and clean it of metal shavings and carbon deposits.
- Remove the old filter and install a new filter device.
- Reassemble everything in the reverse order, not forgetting to change the seals on the pan and the drain plug.
- Fill in new flushing oil as much as was drained.
- Now you should disconnect the return hose from the cooling radiator and insert the free end into a five-liter bottle.
- Ask your partner to start the engine.
- A black liquid will flow into the bottle. Wait until it changes color to light.
- Drain all oil.
- Turn off the motor. Reinstall the hose.
- Add as much original lubricant as has spilled out.
This will complete the cleaning step. The old oil was replaced by new oil. Car owners believe that this is enough to flush the automatic transmission. Some people use cleaning additives in this case, although experts do not recommend it. Since their effectiveness has not been proven, various impurities can harm the automatic transmission.
