Transmission - When did yours die?

[upallnight]

Originally Posted by JCL

If it is shifting fine, I wouldn't do anything to it. If it is not shifting fine, do a fluid change and make sure you change the filter. Has shifting changed recently?

Don't worry about GM Powertrain. The shifting characteristics were determined jointly by BMW and GM Powertrain. It shift firmly but smoothly.

The 3.0 does not have a ZF transmission. Follow the tag on the transmission, but I expect it was Dexron III, now upgraded to Dexron VI.

Diffs aren't a problem to do.

Transfer case is similarly straightforward. It isn't x-drive, so I believe it is Dexron again. No computer reset required.

Normally when people have problem with their trans it is usually too late for a fluid change. People do the fluid change hoping that it will fix the problem, that if they have done regular maintenance they might have avoided the problem. As for Dexron VI being compatible with Dexron III, GM approve of it for THEIR cars and trans, not other manufacturer's trans.

"Dexron VI-the newest GM ATF, it was developed specifically for the new six-speed automatic and is a synthetic blend (meaning it has some conventional base stocks). That transmission has tighter internal tolerances and required a fluid that had higher shear strength that Dexron III. It was introduced with the 2006 models. GM considers Dexron VI to be "backward compatible," meaning GM recommends it for use in any vehicle that originally used any earlier version of Dexron and that it can be mixed with them. However, GM specifically recommends against using Dexron VI in non-GM made vehicles that used Dexron III as original equipment. GM brand vehicles that have non-GM transmissions, as mentioned above, or are imported to the United States." A Chevy Nova which is really a Toyota would not be a candidate for Dexron VI.

Even though BMW never used an Allison transmission in any of their cars, the seals that were used in the Allison transmission may have also been produce by the same company that provides seals to GM. There was a incompatibility issue with Dexron VI and the seals used in the older Allison trans.

[JCL]

Originally Posted by upallnight

As for Dexron VI being compatible with Dexron III, GM approve of it for THEIR cars and trans, not other manufacturer's trans.

Yes, but BMW call for it as well, so I wouldn't worry about the Allison seal issue.