DIY automatic transmission oil change

[Dackelone]

Originally Posted by froop

I want to do the service but I'm also worried that it might not fix whatever's going on in my tranny...

Earlier this year I bought an old BMW e39 535i V8 auto. It has a ZF auto in it. The car has LOTS of kms. 240K kms when I bought it. The trans would not shift sometimes. On WOT the gear shifts would slip and bang at times. One cold starts(car is parked outside most days) when I would pull away the trans would loose 1st gear all togetehr. Or sometimes when it would shift from 1st to 2nd gears... all I would get is no gear. Even though I was in DRIVE! I was really worried the trans was dead. I was also getting codes for "emergency limp mode" on my board display.

I decided to pull the AT pan and change the fluid. I was really worried my trans would die shortly after servicing it. I was wrong. So wrong.

Changing my cars trans fluid was THE BEST thing! Now it shifts like a totally different car! So much smoother and crisp. Only when the trans is cold and I do a high rpm WOT shift from 3rd to 4th, does the gear change bang a bit. But I normally don't drive like that. I would say changing the trans fluid has fixed 97% of the way my trans was shifting. I am so glad I did it. AND it is so easy to do!! IF you can change your engine oil... you can change your automatic trans fluid.

The hardest part is having the car up (level). Then you need to drain the fluid( not a big deal bc ZF gave us a oil drain screw! Then you pull the AT pan off (30 torx bolts) remove the old gasket and clean the surface and install a new filter and reinstall the pan/gasket. Then fill up with new oil. NOW... here is the hard part. You have to pump in new AT oil until it spills out of the trans. Then put the fill plug on, and start the trans WITH it in drive. Run the trans thru ALL the gears. Reverse, Park, Drive, 1st thru 5th gears. Then leave it in DRIVE and let the rear wheels spin. Leave the car to idle in gear for 20 minutes. Then remove the AT "fill plug" and start pumping in MORE AT fluid, until it spills out again. RUN the AT thru the gears again and recheck.

THE most important thing to remember is... DO NOT turn the engine off with that fill plug open! Otherwise alot of your trans oil will come spilling out!

I ended up changing my trans fluid three times over 1.5K kms. My trans holds 13L of oil. But the AT pan only has about 5.5L in it. So I kept changing the oil until the old oil would come out red. The first few times it was black, then brown, then red-ish in color. I think I changed the trans oil four times. I really wanted to get out ALL the old oil in the torque convertor and AT cooler lines. I have driven my car about 8K kms since I serviced it and I am so happy I did it!

I used Liqu Molly AT oil, since it was the only reasonably priced oil in Germany I could find. Most AT oils were 300 to 450 euros for 20L. I paid 120 euros for 20L jug.

Also interesting is that when the trans fluid is low... the trans will go into "limp mode". SO it is critical that the proper trans fluid is used and the proper amount of fluid it used/put in the trans.

Like I said... I was so glad I did this AT service. It is so stupid that BMW says not to change the fluid WHILE the people who make the auto trans (ZF) say to do it every 80K kms. IF you plan on keeping your car... change your fluids!!! My e39 has 270K kms on it now and it shifts just like new!

[froop]

Thanks so much Dack. Definitely puts me at ease knowing like a service might fix the tranny issues. Definitely didn't want to have to fork out to replace the whole thing...

[MrClean514]

Awesome stuff in this thread! Very helpful! Going to tackle this mo-fo this weekend!

[vodycolk]

Can anyone chime in and answer a quick question for me.
I am having an issue with the AT in where I take my foot off the brake (While in D) and it doesnt do anything for half a second, then clunks and starts rolling forward. has anyone had this issue, or knows if a AT Fluid flush would fix it? Thanks

[Atomic Drifter]

I have a 2010 128i with the GM 6L45E transmission. I was at the dealership getting the oil changed and inquired about when the tramission fluid would need to be changed. I was told the transmission is sealed and the fluid is for life. Has anyone had any experience with these transmissions and is there anyway to replace the fluid?

Thanks

AD

[pj.rodriguez]

Originally Posted by Atomic Drifter

I have a 2010 128i with the GM 6L45E transmission. I was at the dealership getting the oil changed and inquired about when the tramission fluid would need to be changed. I was told the transmission is sealed and the fluid is for life. Has anyone had any experience with these transmissions and is there anyway to replace the fluid?

Thanks

AD

I was told the same thing. But you can definitely change the fluid. There is a DIY done in this thread as well as one done by Froop in a different thread that I just commented in. Check out the DIY section and it should be on the first page.

Hope that helps!