anaksarawak
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planta;269873 said:There are a few reasons to remove the gearbox instead of just a std drain and refill. It is something to be considered when you car hits above 100k mileage. It is more or preventive service rather than a repair. If your GB is damaged such valve body or clutch damaged, changing the ATF will not fix the problem.
First is to change a torque converter seal and 2 output shaft seals. The output shaft seals tend to worn out at about 100k mileage. You can see some oil and dirt at the seals that indicate that there is a leak. Thus, no point adding new ATF if it is going to leak out.
Secondly, it ensures that you can remove almost all of your ATF as you can pull out the torque converter and turn it upside down to let the ATF to spill out. Draining will only remove the ATF contained by the oil pan and some above the body valve. It will not remove the ATF inside the torque converter which contains between 50% to 60% total ATF in your transmission. This is more of a practical call. At 100k mileage would you want your transmission to run with 50% to 60% ATF that has clocked ~100k mileage? You can decide when you see the color and smell of the ATF when you drain it out. 100k used ATF will definitely turn off a BMW lover and I don’t think you would want the balance used ATF in your torque converter. But then again, it is your call.
Thirdly, when you detached the GB, you can change the flywheel oil seal too, which again, it normally worn out after 100k mileage causing engine oil spill. I just saw this on an E46 318 2.0 2002 last week. The flywheel oil seal leak + 2 transmission output shaft seal. Mileage 105k. So we changed the strainer, seals, gasket and ATF.
I did not include the output shaft seal in this picture. Only shows the torque converter seal, strainer and oil pan gasket.
Unfortunately for this car, the oil sump also leaked, thus we had to remove the engine oil sump and change the gasket too. It was not an easy thing to do.
Since we have removed the GB, it is easier to access to the head plastic water stopper. We changed this too coz at 105k and it could break anytime. This thing cost less than rm70 but if it breaks coz an overheat which the cost will be ??? you do the math.
Inside the oil pan, there is a magnet that is supposed to stick all the steel debris inside the transmission. When you remove the oil pan, you can see whether the debris is thick or thin. If it is thin, then it is normal but if it is extremley thick, it may indicate that your GB has a serious problem. We saw this on a GM trans on an E36 318 last 2 weeks. It had an unbelievable thick debris and when we pulled out the torque conv, there was very little ATF. Apparently, the ATF leaked for some time from all 3 seals and there was insufficient and overused ATF in the transmission. That is why the car was so sluggish and the trans was humming. We told him it was not recommended to service the GB. We were not confident that it will be ok after service. He decided to buy a 2nd hand trans and we serviced the 2nd hand trans and installed it for him.
Flushing in my opinion is expensive and ineffective, therefore not value for money. Flushing requires a lot of new ATF as you pump in and suck the ATF at the same time to dilute the ATF by mixing the used and new till you can see a lighter ATF color flowing out that indicates almost all of the ATF in the GB is new. Why I say this is ineffective is that, flushing is done without removing the GB and no seals change is done. Why spend on a lot of ATF but it might leak after a while? When the oil seal leaks, you still need to remove the GB.
Another info to share which I am not sure but I was told that there is an additional item for E60, which is you need to change the aluminum screws when you remove the GB as the strength of the screw is compromised when it is remove and it might break when you put it back the 1st time. Unlike previous models, it uses steel screws. Thus, you need to change the whole screw set for E60. Can someone confirm this?
Pls note that I am sharing my limited knowledge to others in good faith. I drive and love my E46 as much as you guys love your UDM. It is intended not in any way for business gain. You make the call on where and when your service your UDM. Hope the sharing helps you guys in your decision making and taking great care of your UDM.
planta
Great infor there Planta.. thanks for sharing..
