I was wondering if anyone changes their differential fluids. I changed the rear but not the center or front fluid. Also I have heard to just leave your transmission fluid alone. I have checked it and its really black and dirty. I don't think its ever been changed with 154K miles. I am capable of changing it, just don't want to screw it up. Does this also go for the diff fluid or can I change that? 01 A4 1.8t 154K miles...what are your thoughts?

 

i was actully gonna change my tranny fluid and i called up the audi dealer local to me and they told me that audi does not recommend changing the tranny fluid for some reason i kinda wonder this myself.

 

I changed ma tranny fluid when I replaced my clutch...
I used redline 75 90synthetic I think...not 100% sure but something like that
if its all black and dirty like u stated i would put new stuff in there...

 

https://www.audiforums.com/forum/diy-do-yourself-55/b5-5-spd-tranny-fluid-change-sandman-18729/

 

Redline MT-90 in the tranny and Redline 75w90 in the rear diff.

You have to use MT-90 (or another GL4 gear oil) in the tranny because you need a GL4 lubricant and not GL5. GL5 has additives that have a high sulfer content which can ruin your syncros.

Redline 75w90 is GL5, but suited for the rear diff.

I'm assuming you're manual...

 

Its actually a tiptronic. I have heard that with that kind of mileage (150k) that changing the trans fluid will "shock" the system and casuse problems since its used to the fluid thats already in there.

 

Change it but don't flush it. High mileage transmissions should just get a pan drop fluid and filter change... so "they" say.

 

I agree just change the filter and transmission oil. If you have gone that long with out it ever flushed or changed, then dont go crazy on it now it will cause you more problems. Just a pan drop, changed filter, and new oil will be fine just make sure to get the right kind of oil for your transmission not (ATF)