Differential Fluid Needs Changing

[JC5]

I'm comming to the end of the break in mileage with the limited slip differential on the 530. The part manufacturer only recommended replacing the fluid after 500 miles with one that in specifically formulated for LSD's. Logic kinda says go for a synthetic for performance & protection, but hey if there is a different opinion let's hear it.

Any recommendations?

Any fluid preferances for regular open differentials while were at it?

[clutch]

I used Red Line 75W90. No particular reason, just seemed to be a popular choice.

I couldn't figure out if I should have used the 75W90 NS for a 330Ci, or if the non NS is OK.

[vagabond]

Mike Miller from Roundel Tech Talk swears by Redline for the diff, but LSDs need the added friction compounds. I know the stuff for the M3 LSD is about 35 bucks per half liter from the dealer and you need 3 of 'em to fill it. If you don't use it, you get lots of chatter and improper behavior from the clutch packs.

[Nick325xiT 5spd]

The PO of my E46 put Redline 75w90 in 5K ago. That fluid was UGLY when I drained it out. Given how poorly Redline seems to last in my transmissions, I wouldn't touch their gear oil either.

Interestingly, Bob Tunnel used Mobil1 in place of Redline in an emergency, and discovered that Mobil1 ran cooler in his diffs.

Personally, I'd use either Mobil1 or the Castrol SAF-XJ that you can buy at the BMW dealer. Redline is a racing fluid that seems to generally work fine when you change it VERY frequently, but I have not seen good life out of it. (But stay the hell away from Redline MTL. It's flat out garbage.)

[Nick325xiT 5spd]

Mike Miller from Roundel Tech Talk swears by Redline for the diff, but LSDs need the added friction compounds. I know the stuff for the M3 LSD is about 35 bucks per half liter from the dealer and you need 3 of 'em to fill it. If you don't use it, you get lots of chatter and improper behavior from the clutch packs.

Only if you like getting raped. Tischer sells it for half that. Online, too, so you don't even have to drive over there.

[mlytle]

interesting experience with the redline stuff Nick. i have used redline exclusively in every bmw i have owned...street and track... for 20 years. have had good experieces with both d4atf and mtl in trannys. same with a variety of redline oils in my diffs. redline 75/90 already has lsd modifier in it. 75/90 ns does not and is good for open diffs. the lightweight shockproof oil is good for track diffs, but only has about half the lsd modifier in it that 75/90 does. i also run redline fluids in my truck diffs.

[mcoupemindy]

I have redline in my M Coupe diff and tranny. Seems to be working okay. Not much of a noticeable difference.

[Real M3]

My experiences follows that of Marshall's. I use Redline 75/90 in the dif and MTL in the tranny, have for the 11 years I've owned the White Beast and used it for a DD, AutoX and DEs. Never had any problems and have not experienced the issues that Nick has. As Marshall stated the 75/90NS is NOT for LSDs.

YMMV

[Nick325xiT 5spd]

My experiences follows that of Marshall's. I use Redline 75/90 in the dif and MTL in the tranny, have for the 11 years I've owned the White Beast and used it for a DD, AutoX and DEs. Never had any problems and have not experienced the issues that Nick has. As Marshall stated the 75/90NS is NOT for LSDs.

YMMV

In an E46 M3, Redline MTL grinds 2nd when cold and is hard to shift even when warmer. BMW MTF-LT2 clears this right up.
In an E46 328Ci (not mine, a friend's), Redline MTL burned up during high speed driving. I mean smoke out of the tranny, and really awful shifting afterwards. MTF-LT2 also solved this.
In an E46 325xiT, Redline D4 ATF and MT-90 both proved completely unsatisfactory, providing good shift feel for no more than a couple of weeks.
In an E36 M3, Redline D4 ATF was much harder to shift after two weeks than MTF-LT2.

So yes, I really, really dislike Redline fluids. The last two vehicles I bought came with Redline in them, and the best thing I've done for them was to get rid of it.

[Real M3]

In an E46 M3, Redline MTL grinds 2nd when cold and is hard to shift even when warmer. BMW MTF-LT2 clears this right up.
In an E46 328Ci (not mine, a friend's), Redline MTL burned up during high speed driving. I mean smoke out of the tranny, and really awful shifting afterwards. MTF-LT2 also solved this.
In an E46 325xiT, Redline D4 ATF and MT-90 both proved completely unsatisfactory, providing good shift feel for no more than a couple of weeks.
In an E36 M3, Redline D4 ATF was much harder to shift after two weeks than MTF-LT2.

So yes, I really, really dislike Redline fluids. The last two vehicles I bought came with Redline in them, and the best thing I've done for them was to get rid of it.

It's clear that Real M3s and ITS E30s simply don't have enough power to cause issues!

Newer trannys and diffs from BMW may have issues, or it's just Nick's hard chargin' drivin' style! I have heard different levels of success with the MTL.

[Nick325xiT 5spd]

It's clear that Real M3s and ITS E30s simply don't have enough power to cause issues!

Newer trannys and diffs from BMW may have issues, or it's just Nick's hard chargin' drivin' style! I have heard different levels of success with the MTL.

The newer cars (ESPECIALLY the E46 M3) definitely have much balkier transmissions and are a lot more sensitive to fluid choice.

Also, the Castrol SMS-X (MTF-LT2) is just a really good fluid. Which the previous OEM fluids weren't, IMHO. LT2 was introduced in 2004, so it's a pretty recent change. (And many 2004s got LT1 put in them if they required a 1,200 mile service.)

[OwnedbyDuncan]

Put over 215k miles on my E30325i with Redline in the gearbox and the diff with no problems.

Will put Redline the gearbox in my Element but have to use Honda's rear diff fluid.

Dave Apker and the collies

[Car54]

Hate to bring this up but I may be starting to dis-like Redline transmission fluid. I'm running ATF in my Mcoupe currently. The fluid use to start out loose between gears when the trans was cold, and as it warmed up it started to thicken and feel great. I don't know what it is lately....maybe the track season wore it out...but it seems to never get passed that cold transmission liquidy state. I'm having a hard time shifting smoothly. Clearly the synchros are not working well. Anyone want to suggest me a fluid? MTF-LT2? Something maybe for winter weather?

TIA,
Craig

[JC5]

I tried Redline in the diff, anf the car felt bogged down. Put the same weight Amsoil in, and voila, perfect. Car doesn't feel bogged down anymore.