Recommended differential Fluid

[m3f_jwdunn]

Hey Everyone



Ive been searching far and wide for the best Differential fluid

i have an e36 m3 that i want to replaced the differential fluid on.

what is a good fluid for road use?

what is a good fluid for track use?

Do i need Friction reducer?



from what i have found these are all the recommendations

Redline 75/90

Redline 75/140

Redline ATF transmission fluid

Royal Purple 75/90

Royal Purple 85/140

Mobile 1 75/90

Mobile 1 75/140

Castrol fx



then of course oem bme diff fluid which is like $200



i had an e46 m3 and tried to use mobile1 75/90 and it ended up blowing out and axel seal due to pressure. i ended up putting in the oem fluid with frictions reducer and never had a problem again. i'm trying not to stumble down this road again PLEASE HELP



thanks



Jared

[m3f_tbaker474]

There is no real "best" fluid to use. As long as it meets the specs, you should be fine. BMW's original spec was 75W-90, but at some point it was changed to 75w-140.



You do need a fluid with friction modifier built in, so make sure what you buy includes that.



One cautionary note: I've seen some incidents where members with otherwise perfectly functional diffs changed to Royal Purple fluid and experienced failures shortly thereafter. Obviously this isn't hard and fast empirical evidence that Royal Purple caused the diff to blow, but I've seen it happen more then once. Plenty of other people use it with no ill effects. YMMV.

[m3f_jwdunn]

thanks thats good advice. what do you recommend? what do you use?

[m3f_turbo_911]

I used Mobil 1 75/140 when I changed my diff fluid 1k miles ago.

[m3f_pbonsalb]

I tend to use Redline, Mobil 1 or Amsoil. I have Amsoil 75W140 in my E36M3 diff presently.


75W90 or 75W140 works for the E36M3. Your E46M3 required 75W140. You do want the normal version with limited slip friction modifiers. You do not want something like Redline 75W90NS -- the NS is for nonslip and this is not good for most LSD.

[m3f_salty]

I went to the dealer and bought their diff lube. they have some for regular BMW's and some for M cars. I also bought the BMW gear oil (MT2) and it is the best one I have used for shift feel.

[m3f_jwdunn]

thanks this is god advice. do all of these options come with the friction modifier or is it something i will need to add?

[m3f_white-hot]

I used Mobile 1 75/140 when I changed my diff fluid 1k miles ago.

^This.



OP, it just has to say for Limited Slip. If it doesn't then it will not have the friction modifier. Just buy a major brand and you will be fine. I use M1 everywhere in the car, but others like Amsoil and then others like Redline, it doesn't matter. All are good. Throw a dart.

[m3f_das borgen]

what the fcuk is Mobile 1?


are people who misspell it stupid or just don't know?

[m3f_eatsleeplax]

what the fcuk is Mobile 1?



are people who misspell it stupid or just don't know?

+1 for MOBIL 1 75W140, and then 1/2(?) of bottle GM positrac to shut the thing up

[m3f_white-hot]

what the fcuk is Mobile 1?

Mobile Alabama is number 1?

[m3f_das borgen]

Mobile Alabama is number 1?

I mean......they do have leprechauns and bed intruders

[m3f_Braymond141]

what the duck is Mobile 1?

[m3f_das borgen]

for the sake of your soul, I pray that you never go youtube or google "Dolan Duck"



no typo there

[m3f_jwdunn]

Thanks for the Help guys, and the feedback on my spelling. i'll look into getting some MOBIL1



thanks



Jared