Originally Posted By: Triple_Se7en
In most cases with vehicles that have lifetime fluid, the tranny fluid can still be changed, I've had it done to two GMs this past week and the fluid was pretty dark after 100K.
I would recommend getting it done at 100K. Also had the shop change the transfer case and rear end fluids on my 4X4.
ZF recommends a change at 50,000-60,000 miles for their automatics if the vehicle is used for towing, track use, or similar. I plan to change the ATF in my 8HP45 at @55,000 miles.