Transmission fluid and diff. oil change

[Mel A]

How often should one change the transmission fluid and diff. oil?Is every 30k miles sufficient?I'm using Redline synthetic MTL and Redline diff. oil.

Dear Mel,j have just buyed a E34 M5 of the year 89 and now my car is changing oil end other, when my M5 will come back from the official BMW, j shall tell you your answer with precision.Gifo



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Gifo

[RYAN]

There has been discussion about the use of Redline synthetic transmission fluid, being used in these transmissions. I rember that the general census was NOT TO USE the Redline synthetic. I believe that it produced unwanted shifter feel. Suggested solution, was to stick with what BMW used. Regular gear oil. (don't know what weight though.)

Any other suggestions?

[JON]

I have recently put a new Tranny in my 91' M5 and my Tuner, which has been in the racing circuit for over 20years inc. Lambo,porche&BMW, recomended to use the original 'gear oil'in the tranny & rear end. Just keep it serviced regularly and you shouldn't have problems nor need synthetic.

Jon
91' E-34 M5

[Markus Kits]

I have tried Redline in the transmission to improve the shifting,but it did not help.
After that i went back to factory fluid(ATF)and it works much better for me,so stick to the factory recomedations.

Dear Mel,
Today I have tooken back my M5 from official BMW service. I have changed gear and diff. oil. The official rules are: ATF and ipoid 90 SAE oil. I dont know if these oil types are valid in US market: CASTROL TQ-D and SAF-XJ Diff.Z3. Moreover I have asked the time we must change gear and diff. oil; BMW service indicate every 30 Kmiles during one inspection II.

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Gifo