[Ninjasane]

I just did my diff and auto transmission at 53k miles on my e90 335i and just wanted to see if anyone can chime in on my problem. I posted in one of the maintenance thread and I am not getting any responses so I am making a thread to see if I'll have better luck...

I had two jacks in the rear and lifted the front at the forward central jack point until I felt that my sideskirts was parallel to the ground as much as possible(I placed identical oil bottles by the front and rear jack points to see they were about the same height).


DIFFERENTIAL OIL (LRN7591=Castrol SAF-XO from Land Rover at $13.99/L)
I drained my diff and when I went to refill it, only got ~1.2liter(1.27quarts) in. I am worried because I thought would need 2 quarts. I doubled checked and car seemed pretty level on my jacks and kept leaking out(also the drain plug is the fill plug?)

AUTO TRANS FLUID (ZF Lifeguard fluid=Shell M-1375.4 from bavauto.com at $22.95/L)
When I did my transmission I only got in 3 liter bottles in the first time around. I FREAKED OUT thinking I drained the wrong fluid but I found some DIYs to clarify and sure enough I was working on the transmission THANK GOD. I thought this can't be right so I ran the car for a few minutes, went through the gears with my paddleshifters and tried again and fortunately got another 1.2 liter in however this still puts me at about 4.2liters(4.44quarts) vs the 7 quarts. Being worried, I ran the car for another 10 minutes and removed the fill plug to find it pouring out. Now the DIY I found was replacing the whole transmission pan with the integrated filter. Is that why I'm left with the extra 2.5quarts? and should I have replaced the pan?

I wondered if I should just put in the full 2 quarts of diff and 7 quarts of atf but i'm sure too much isn't a good thing either so I just left it as is but I'm so nervous when I drive the car now however the car drives a whole lot better. prior to the atf flush, my 2nd to 3rd was super rough where as now it feels smooth and effortless....should I still be worried?

[Bcube]

1.2 Liters in rear diff for the N54 & Diesel.
1 liter in rear diff with N52.

Some one else will have to answer the AT question.

[Ninjasane]

okay so my diff is good! thank you for that info Bcube! i read somewhere that i would need 2 quarts i guess he meant more than 1.

can anyone answer my AT question?

[queensfield]

For AT fluid: with the car level and engine idling (to reach about 30-40C), if you see a small stream of trans fluid running out of the filler plug, then the level is correct. Since you did not drop the pan, you have not drained the trans fluid completely (minus some remaining in the torque converter). This explains why you needed less fluid. Since you are only at 53K miles, complete drain and pan / filter replacement may not be necessary- but that is your choice and your decision. If you are encountering no problems, then leave it. Your drain and fill should be sufficient. You can replace the pan plus filter with another drain and fill at around 100K miles. However, if you are encountering shifting problems, then drop the pan, which will drain lot more fluid, and then replace the pan plus filter with a new one. You should also change the mechantronic sleeve, if you are going to do that.

[Ninjasane]

appreciate it! thank you for that peace of mind! i will be more attentive to how the car shifts and be the judge of whether to add more or not. happy new year!

Originally Posted by queensfield

For AT fluid: with the car level and engine idling (to reach about 30-40C), if you see a small stream of trans fluid running out of the filler plug, then the level is correct. Since you did not drop the pan, you have not drained the trans fluid completely (minus some remaining in the torque converter). This explains why you needed less fluid. Since you are only at 53K miles, complete drain and pan / filter replacement may not be necessary- but that is your choice and your decision. If you are encountering no problems, then leave it. Your drain and fill should be sufficient. You can replace the pan plus filter with another drain and fill at around 100K miles. However, if you are encountering shifting problems, then drop the pan, which will drain lot more fluid, and then replace the pan plus filter with a new one. You should also change the mechantronic sleeve, if you are going to do that.