Mixing Dexron fluids

My BMW E46, with GM transmission, currently has mostly Redline D4 in it. I dropped the pan, changed the filter, and refilled it roughly a year ago. A month after, I drained and filled again with more redline D4.

The D4 is supposed to be closer in viscosity to Dexron III compared to Dexron VI.

I don't really think the Redline fluid is necessary compared to any other synthetic Dexron, and I don't believe any longer that it's necessary to use a fluid that's closer to the original Dexron III. I would like to do the next drain and fill with something cheaper, like synthetic Havoline Dexron VI.

From what I understand, I'll be left with something like 50/50 Redline D4 to Havoline Dexron VI if I drain and fill. Is it okay to mix these fluids? As it is now, the D4 probably has a good amount of the original factory fill fluid mixed in with it because I've only drained and filled twice so far.

I've mixed DexIII and Dex VI numerous times in my Cherokee. And not an issue yet.

It's a good thing you are at least doing drains and refills as this replenishes additive chemistry and reduces particulate loading of the lubricant.

Dexron VI and MaxLife and D4 are mixable and have similar dynamic friction coefficients.

I plan on mixing Dex III and Maxlife together in the transfer case, see what happens. Its very picky, shudders cornering on straight Maxlife, but clunks and rattles on straight O'riellys Dex III.

Originally Posted By: LeakySeals
I plan on mixing Dex III and Maxlife together in the transfer case, see what happens. Its very picky, shudders cornering on straight Maxlife, but clunks and rattles on straight O'riellys Dex III.


Then it may not be the fluid. You may have worn TC internals.

Originally Posted By: MolaKule
It's a good thing you are at least doing drains and refills as this replenishes additive chemistry and reduces particulate loading of the lubricant.

Dexron VI and MaxLife and D4 are mixable and have similar dynamic friction coefficients.


I also have roughly 1 and 3/4 gallons of Amsoil Signature Series ATF. Can I mix that with the Redline D4 that's in there right now?

Originally Posted By: MolaKule
Originally Posted By: LeakySeals
I plan on mixing Dex III and Maxlife together in the transfer case, see what happens. Its very picky, shudders cornering on straight Maxlife, but clunks and rattles on straight O'riellys Dex III.


Then it may not be the fluid. You may have worn TC internals.


Yes probably true. It went 100k on the factory fluid (dexIII). When I changed it was black.