Transmission Fluid (oil thread part 2)

[oceansize]

Ravenol was identified in many of the old threads as a suitable replacement and it is what I have been using for the last 5k miles without issue or complaint. I am in no way an expert just following what some of the more knowledgeable guys in this area identified.

[Nuclear Rabbit]

... and they don't make a fluid that meets the specs of our trans

If I'm not mistaken, BMW specifies 75w90 API GL-4 fluid for the 420g in our cars, which is the same specs as the MT 90 mentioned in the original post

I don't want to seem like the redline defense force but there seems to be some weird stigma in BMW forums (m5board included) about redline. Are there any instances of it failing on someone or destroying their trans? I've seen a few blackstone analyses of it and people don't seem to report any unusual or high wear (although none specific to the 420g).

[Speed Monkey]

Royal purple is just crap, for all use cases.

Just kidding Ian. Don’t ban stick me. 😋

[Obioban]

Use this! Ehh, just kidding, don’t use that. I remember this was discussed at length in the old days on M3F. 🙃

Royal purple is just crap, for all use cases.

[Speed Monkey]

Use this! Ehh, just kidding, don’t use that. I remember this was discussed at length in the old days on M3F. 🙃

[Obioban]

What about redline products make them not suitable for street use?

Race fluids are designed to be replaced after every race and give no consideration to low temperature performance.

[Nuclear Rabbit]

I just switched out to the "redline cocktail" of 1 qt MTL + 1 qt MT 90 about 1000 miles ago on my 6mt. Used to use this mix in my evo x / eagle talon which I tracked heavily and never had any issues. So far I've noticed that the car is a bit quieter at speed and has some more smoothness between gears. They are a bit more "grabby" to stay in place and I don't have any issues with 4th gear popout anymore. I remember swapping out the fluid on my e39 M5 (same trans) for pentosin MTL-2. If I had to compare (entirely subjective) I'd say that the MTL-2 feels even smoother and heftier, albeit not as quick going between gears.

[DESMDR3]

Redline products are not the best for use in street driven cars.

... and they don't make a fluid that meets the specs of our trans, so in that specific case, not great for track use either.

What about redline products make them not suitable for street use?

[Obioban]

Redline products are not the best for use in street driven cars.

... and they don't make a fluid that meets the specs of our trans, so in that specific case, not great for track use either.

[Arith2]

While I do have fun with oil threads, I do genuinely like reading what people's experiences with different fluids are. I had some MT-90 sitting around because I accidentally used the oil I was saving for my M3, on my temporary replacement car. I thought my MT-90 was MTL but I didn't check until months after when I needed it. Things have just been stored in closets. Well I threw some of that in because I'm curious. Will it suck? Maybe. Will it help counteract my lightweight flywheel a little, hopefully enough to allow the SMG to figure it out.

Anyone use the MT 90? Anyone tested this and OEM fluid side by side in an SMG or just manual?

There used to be a thread on this. I'm more than happy to hear about other fluids.