Allison Spin-on Filter Change

[Robertaz]

Are there any problems caused by filling the new filter with Synthetic ATF? This mixes about a pint with the OEM ATF, which I assume is not synthetic.

[DmaxMaverick]

Robertaz

It depends on the brand of synthetic fluid you are using. Most that I am aware of are compatible with mineral Dexron III. Check the label and it should indicate whether it is or not.

Since you are changing the filter, why not drain and fill the pan also? If your fluid is compatible with Dexron III, then fill the pan with the synthetic. I did this before flushing and completely replacing the Dexron III with Amsoil synthetic. Also, I noticed no difference when the filter was filled before replacing, or not, but surely doesn't hurt. Cheers

[Robertaz]

Thanks for the advice.