How to repair an AMT gearbox | Team-BHP

2022-03-24 11:12:10 By : Ms. Bella Li

BHPian Keneida recently shared this with other enthusiasts.

I went through the forum and this post got me interested.

I've repaired the AMT unit of my 2015 Celerio myself and there is a simple trick to do it if the damage is not major. I own a FNG. AMT jerks or get jammed due to metal emery or fine dust in the clutch actuator, clutch is not to blame- I repeat clutch is not to be blamed (I have changed 3 clutch sets for resolving jerk issues, the clutch plate was like brand new all the time.

Step 1: Get the entire unit out, there are only 3 screws holding it in place, it should not be disassembled and removed else the oil spills everywhere, the entire unit must be removed as one.

Step 2: Check the colour of the oil, it has to be golden like sunflower oil, Grey or black oil means there is a need to change the oil.

Step 3: Remove the filter, it has an approx. length of 4 inches and 2.5 inches diameter, there is a star socket under it, it can only be opened with power tools and not a torque wrench.

Step 4: Unscrew the entire filter and to your surprise, there will be thick grey fluid, Its actuator oil mixed with fine metal particles from the amt unit. take a magnet and stir in it you will find sub-micron metal filing in it.

Step 5: If you do not find thick grey fluid here, then no problem your AMT hydraulics, AMT has another issue, put the filter back and go to an authorized dealer and get your AMT unit re-calibrated, costs 1003 rupees with GST. (1% of the people will get away with this method follow.

Step 6: onwards for the 99% unlucky ones) Step 6. This is where we need to disassemble the unit in a systematic manner.

Step 7: Drain the grey liquid from the chamber where the filter fits ( unfortunately you cannot buy this hydraulic filter from any authorized parts dealer as this filter was made in Collab with SIAC and Magneti Marelli and the origins of this filter are Chinese, My friend a BHP member contacted Leoshashi for the same, there is no part code for this filter)

Step 8: Get yourself an AMT oil, do not use the ATF fluid or red ATF or brake fluid ever. The oil that I use is Bantex power, Dexron-VI ATF 1 liter. In this case, you will need 2 cans of oil approx. 1.2 litres combined not more than 2 litres.

The one made by Honda is also available. It is packed in 800 ml - 1 liter red or white color container with red cap, the oil is clear in color, Bantex oil is gold in color. Ive seen some FNG's using red color ATF fluids, they gum up later. Bantex is some kind of repackaged oil, its locally available, couldn't find online links to the product page.

Step 9: Use eye protection like a safety goggle or face shield here. Open the actuator cover: It is a cylinder 6 inches long with a rubber boot on it. this actuator has a small cover at its end. The cover is secured with a circlip. Remove the circlip using the circlip pliers. the cover has a 7 cm x 4 cm square button on it. Use a plier and simply pull this cover, there is no spring behind this unit so no worries, the oil may shoot in the direction of your face, use eye protection. The plug (cover) has an o-ring, inspect it.

Step 10: Pull and push the actuator extension coming out of the boot, it is flexible and moves in and out. By doing so you will remove a lot of emery inside this cylinder. keep on doing it until you are sure that the cylinder is moving freely, there is a sensor on top of the housing, it's a magnetic pickup unit, don't try to remove it.

Step 11: Pour some fresh AMT oil into this cylinder and do the back and forth process to make sure that the new oil has replaced the old one. Seal the actuator back as it was disassembled.

Step 12: Things will get messy now, use a large tray and apron for the next operation. remove and separate the oil container and sub-assembly of the AMT unit. There are a few green coloured O rings, keep them safe.

Step 13: Once you remove the oil container oil spills out everywhere, drain every drop of oil, use rust off or oil degreaser inside the oil container, you will see a ton of emery coming out from the crevices of the AMT sub-assembly. Clean it thoroughly, use a spray like WD40 to thin out the greasy substance. The rust off I use is made by Wurth or related brand, it should be rubber friendly.

Step 14: Keep the unit subassembly tilted to allow draining of remaining fluids by gravity.

Step 15: after an hour or so. once the unit is cleared off all the fluids, grease the o rings and assemble the unit back.

Step 16: Put in new oil and reassemble the unit back on the gearbox Oil can be topped up anytime but I prefer before putting the unit back on the gearbox for detecting leaks.

Step 17: Just give ignition with the key, do not start the car. Let the hydraulic motor recirculate new oil.

Step 18: After a minute or so. start the car cycle through D and R mode. and stop.

Step 19: If everything works fine great else you may have to slightly calibrate the unit until it works satisfactory, this is done the same way as you adjust the manual clutch. The mechanic knows how to do it.

Step 20: go for a short drive and return back to the FNG, Remove the AMT unit again and repeat steps 4-6-8-9-10-11. Do not disassemble the entire unit just the filter and actuator cylinder to remove the remaining debris.

Fill in fresh oil in the cylinder, not the container (don't worry about air bubbles, they end up getting back in the oil container) and fit the unit back on the gearbox.

Step 21: Take your car to the authorized service centre. and do a calibration with their scanner, which takes 20 mins costs Rs 1003 with GST, once done you are good to go. This exercise will cost Rs 4-5K if the prevention is done once you start to feel jerks, if gears get stuck then there is a 50-50 chance of overhauling else replacing the entire unit.

My car works fine, we drive it to work, a fellow BHPian is the eyewitness of all the things I improved with my car and how it turned out to give results.

Here's what BHPian audioholic had to say on the matter:

Hi Keneida, thanks for the informative description on the whole process of overhauling the AMT. I had one question in mind. During the replacement of the fluid especially at the clutch solenoid, what happens if there is any air trapped in the fluid lines? Would it get automatically bled out of the system during the repeated gear changes or would it get stuck in the system? The bit about cleaning the clutch solenoid and replacing the filter/fluid is very interesting. But in this process I do not want to introduce air into the system or worse brick the AMT unit itself since I am sure the only way to go then would be to replace the unit. Also I had another query in mind. Would replacing the oil in the reservoir do any good to the overall performance of the AMT? I am not able to see any pictures in your description and try to understand the location of the filter. If this is possible without removing the AMT unit, I would want to try replacing the oil and the filter, and then repeat this process until the old oil has been somewhat replaced with the fresh one. Is this possible?

Here's what BHPian Keneida had to say on the matter:

Hello @Audioholic, I am working on making a well documented procedure for TBHP. I have recently joined TBHP so it will take some time for me to get used to the interface, especially how the quotes work. So, Its a hydraulic solenoid/actuator for Maruti Suzuki. I was afraid of air lock, I had prepared myself for that uncertainty by dialing a vendor in second hand market. But upon pushing in and out of actuator the trapped air went on to accumulate in the oil reservoir, so trapped air finds a way out that's well engineered, hence In all the steps mentioned the oil stays in the system only specific bits like filter and actuator get isolated unless a complete disassembly. There are violent gear shifts and juddering if air is trapped, best way is to keep the ignition on and let the hydraulic motor do its job for a minute or 2 (you can hear the sound), while doing so keep the oil filler cap open. This is to be done with the help of a experienced mechanic. Regarding oil change, It would not help as there is no drain plug, even if you manage to take out the oil container, The culprit is Metal Emery, The best way to eliminate it is to find a brand new filter which sadly has no identification in MS service books. I am going to write to Magnetti Marelli India for the same #Righttorepair. I am attaching some pics of the filter. Right now the method I've suggested is similar to dialysis with manual intervention through filter chamber and actuator module. Regarding performance: The difference is day and night, I had a back to back test drive of A6 and Celerio, For some time I felt that AMT was performing brilliantly it was still apples to oranges but once you get some muscle memory from something superior like a DSG then you could nitpick minor flaws. This was when I had a new clutch and the AMT had undergone the dialysis, now the clutch plate is settled in so old days are back. Still I feel AMT has the potential if executed well. Also, My car was from the batch of early adopters for AMT, The gearbox sealant is still present on the outer periphery of the casing, meaning it was modified on shop floor to fit in the shifter mechanism for AMT unit ( which is different for Manual transmission ), ideally the sealant is not exposed, nor have I ever disassembled the gearbox so this could only happen if the sealant was applied manually.

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