6MT Transmission fluid recommendation?

[Harpua]

2008 E90 M3 6MT with 80k km (50k miles) and it's about time for a transmission fluid change. My car is now out of warranty so I am wondering what the M3 experts are recommending as a fluid replacement.
I'm using my car as a DD and continue to drive it through the Canadian winters. I have not tracked it yet.

Redline MTF? Royal purple synchromax? Stick with OEM? Other brand?

Thanks in advance

[Small Yellow]

Motul 75w90
Royal purple syncomax
Oem
Etc, theres a thread somewhere with a list of fluids available.

[Harpua]

Originally Posted by Small Yellow

Motul 75w90
Royal purple syncomax
Oem
Etc, theres a thread somewhere with a list of fluids available.

Thanks. I am aware of the alternatives available but was hoping for some first-hand experience reports with use of the different products, why they were chosen over OEM, potential benefits, drawbacks etc.

The default will be to just use the OEM fluid as replacement, but being that I'm out of warranty I have the option to use other products without recourse.

[apecush]

Redline d4 ATF for the 6MT. Using it in my car that sees everything from the track to cold winter driving. I have absolutely no complaints.

[dparm]

You need a GL-4 75w80, as that's what the OEM fluid is. Red Line makes such a fluid.

You could also run 75w90 GL4, which might be preferable if you are tracking the car. 75w90 also gives you many more options, such as the fantastic Motul Gear 300.

[Z K]

Originally Posted by apecush

Redline d4 ATF for the 6MT. Using it in my car that sees everything from the track to cold winter driving. I have absolutely no complaints.

This is what I use. Redline D4 ATF for transmission fluid. It's what Redline recommends too.

[italyix]

Originally Posted by Z K

This is what I use. Redline D4 ATF for transmission fluid. It's what Redline recommends too.

I run Redline MTL and it is smoother than stock even when cold (been hitting 32 degrees here in the morning). I do have to say though, I should have heeded Z K's advise and run D4...which is what I plan to switch to shortly along with my oil change to M1 0w-40.

[dparm]

Just to clarify, not all ATFs are safe for a manual trans: the D4 stuff is unique because it also a GL4. I'm actually surprised you guys are running it, as it is some 50% thinner than the factory 75w80.

[meko]

I've used redline MTF in other cars but not this one yet. Recently had a service at dealer and they used the new LT-5 fluid. (Think thats what its called). It made a noticeable difference. Not night and day but I was impressed. The next time I change it myself I will probably use it. Just my 2 cents.

[W///]

When it was time to switch mine, I went back to OEM. Same with my diff fluid.

[apecush]

Originally Posted by dparm

Just to clarify, not all ATFs are safe for a manual trans: the D4 stuff is unique because it also a GL4. I'm actually surprised you guys are running it, as it is some 50% thinner than the factory 75w80.

do you have any data to support that?

D4 atf is 7.5 cst at 100C

SAE specifies the viscosity range of 75W80 is 4.1 - 11 cst at 100c. What is the viscosity of the BMW fluid?

[dparm]

Originally Posted by apecush

do you have any data to support that?

D4 atf is 7.5 cst at 100C

SAE specifies the viscosity range of 75W80 is 4.1 - 11 cst at 100c. What is the viscosity of the BMW fluid?

The OEM fluid is Pentosin Titan Sintofluid 75w80, and the specs are as follows:

KV @ 40C = 49.8
KV @ 100C = 9.4

I may have misspoken about it being 50% thinner, but it is about 25-30% thinner. Not saying it won't work, but that's pretty far from the OEM fluid for me to call it completely safe. Red Line's 75w80 is far more appealing.

To be clear, BMW does NOT spec "[any] 75w80 GL4", but their fluid happens to be that.

[jimk]

I have actually been very impressed with the OEM fluid. The tranny shifts smooth even at temps below zero. It is a little notchy going to second gear at the first drive off but it gets better after a few minutes. I never force it into gear, I just choose the next gear up during warmup.

[MFKN3]

Originally Posted by meko

I've used redline MTF in other cars but not this one yet. Recently had a service at dealer and they used the new LT-5 fluid. (Think thats what its called). It made a noticeable difference. Not night and day but I was impressed. The next time I change it myself I will probably use it. Just my 2 cents.

Do you know if LT-5 is now recommended and has replaced the LT2 for the S65? Last I thought it was for 1M's.

I was thinking OEM or redline D4. Troubling though the specs differ so much. Would the thicker OEM be better for track use?

[meko]

Yes LT-5 is now the fill at dealer. Part # 83222239654. This is the part # for the 1 liter size. 3 liters are required for the change. I'm a big fan of Redline, but after this last trans fluid change I will be sticking with the LT5.

[dparm]

Originally Posted by MFKN3

Do you know if LT-5 is now recommended and has replaced the LT2 for the S65? Last I thought it was for 1M's.

I was thinking OEM or redline D4. Troubling though the specs differ so much. Would the thicker OEM be better for track use?

Thicker is not always better. You want as thick as necessary, but as thin as possible. The knee-jerk reaction is to always say, "oh I should just go thicker since I race the car."

If the OEM fluid is not too expensive, go for it. Otherwise, there are other GL-4 75w80s available (Red Line, Valvoline, Mobil, etc). I'll let some of the 6MT track rats chime in here, but a 75w90 is probably fine too and would open you up to a lot of outstanding fluids like Motul Gear 300, Renewable Lube Gear Oil, Castrol TAF-X, etc.

[MFKN3]

Thanks everyone. I might try OEM LT-5 since redline D4 is quite different.

However, I can't seem to find any info that BMW are recommending it for our 6MT, as everything points to N55 or 1M.

[dparm]

Originally Posted by MFKN3

Thanks everyone. I might try OEM LT-5 since redline D4 is quite different.

However, I can't seem to find any info that BMW are recommending it for our 6MT, as everything points to N55 or 1M.

I believe there is a sticker on the bell housing that tells you which fluid to use. It should be bright yellow.

[meko]

I will see what I can find on this.

[thekurgan]

Redline's MTL works quite well in this tranny, granted I don't see ambient temps < 30 often, but once it's warm, it's quite smooth.

[Iyzmi]

Originally Posted by MFKN3

Thanks everyone. I might try OEM LT-5 since redline D4 is quite different.

However, I can't seem to find any info that BMW are recommending it for our 6MT, as everything points to N55 or 1M.

Originally Posted by dparm

I believe there is a sticker on the bell housing that tells you which fluid to use. It should be bright yellow.

I haven't looked yet but I imagine the bell housing will show LT-2 as the requirement. This thread is now over 3 years old and I still haven't seen anything official from BMW recommending LT-5 for the E92 6MT. I'll probably just call my dealer and see what oil they would use, but does anyone have any concrete info confirming LT-5 is now the recommended fill for the E92?

Also, is it ok to mix ~2L of LT-5 with the ~.5L of LT-2 that will be in the cooler lines assuming the transmission pump is not activated? I'm looking into buying a diagnostic cable/software to be able to activate the pump but haven't decided if it's actually worth it. FYI - this is what I am considering:
http://www.bcables.com/index.html

[dreamspeed]

I used Redline MTL but when I emailed Redline they actually recommended Redline ATF