Planning on chaniging my rear end gear oil and tranny fluid soon. what rear end gear oil shoul di use? synthetic or regular? looking at brents page and he used the mobill 1 75w-90 synthetic gear oil. i know i need a bottle of th limted slip addtive from gm. is 75w-90 a good weight? on my tranny fliuid same thing should i use synthetic or just regular. aslso what weight shoul di use? im thinking of useing honda's auto tranny fluid or the manual trannyfliudi. i know it works wonders for hondas and other cars i have heard to. also where can i get the gasket for the rear end. do i just go to the dealership to get it? how much is it and what part number is it. brent has liststed a felpro where do u get that? i am going to get teh gasket and use the high temp rtv gasket maker like brent did. better to be safet ehan sorry. what do you guys use and do? thanks lmk asap i plan on doing this soon. i want my shifts to be smoother and better while my rear working smoother with fresh lubricant also. tahnsk again.

 

I can't answer the rear diff question but as to your question regarding the transmission, you should have the entire transmission flushed out, not just the 2 or 3 quarts in the pan. Also I've heard that synthetic was not good in the transmission (forget the reasons now), but I had mine completed flushed and I used 2 quarts of synthetic for just the pan capacity. Also don't forget to check the fluid level when the car is hot and in idle.

 

You can get the gaskets at most auto parts suppliers. I got mine at Autozone I believe. (rear, transmission, transmission filter). But mines an automatic.

 

I bought a new gasket when I changed the fluid in the differential and have yet to use it. I've changed the fluid twice and the gasket looked fine and sealed right up when i replaced the cover. Doesn't leak a drop and the new gasket is still in a drawer.

 

He has an M6 trans not an A4. No need to flush it, just drain it. I'm using Mobil 1 ATF in my M6 trans and I used to use Mobil 1 75/90 in my old 10 bolt rear with LSD additive. You can get a rear cover gasket at any parts store for a couple dollars I believe.

 

yep ur right. i was going to post back also wondering why i owuld need to flush my M6 haha. yea i just need to drain and refill it. Can i get the mobil 1 Atf from a regular auto parts store like autozone, advance, napa? is the mobil 1 75/90 a good weight for the rear. what do you use now? thanks let me knwo.

johnd. ok i havent changed my rear end oil since i got it and i dont knwo ift hte gasket will still work like urs did. i had already planned on buying a new one just incase and since u guys say its only a few dollars thats better to have it there already just incase my old one right now is wore and so forth. thanks for all the replies. i think i might go with either the mobil 1 atf or the honda atf-z1 for my tranny fluid. i searched for a few threads last night about it also and people said the atf-z1 is aweseom for improving shifts and so forth. should be almost 4 quarts for the acapacity of the tranny as said on brents page. his page really helped me out. for the rear i guess ill go with the mobil 1 syn 75w-90 2 quarts of that and the lsd additive from gm. everywhere i have searched and read on this board it is a MUST. so i will make sure to add it also. dont want the lsd to be burning up. thanks guys. any problems i should look out for. i plan on squeeezing the hell out of these bottles to fill them up like brent did. i think slp makes a rear cover that has a dran and fill hole but its like 80 bucks or so. not wroth that to me. if i ever get a new rear then i will get one with the drain fill holes. stupid **** gm forgot to put one in there. haha. how often do you guys change your tranny/rear end fluids? i havent done it yet and this will be my first time in about 13k miles so i know it needs it and it will help. i love smooth shifts. thanks