Join Date: Dec 2008
Location: Tyler, TX
Thanked 407 Times in 347 Posts
It depnds on the ATF condition
If you PULL with your car/truck, then the 100,000 mile "ok to change window" does not apply, and for many vehicles the "safe" uppre range is much closer to 70,000 miles in "normal" service.
ATF contains calsium, with increased HEAT (the biggy) and age more an more calsium is absorbed by the friction elements (clutch pack), this makes the ATF VERY grippy. Since all modern electronic transmissions have "adaptive shifting", the PCM DECREASES line pressure to keep the factory shift feel with the grippy old/burned ATF.
When you change old or burned ATF the friction elements have much more calsium build-up than normal, and the new ATF has a fresh supply of it as well. Combined with low line pressures, this makes the shifts SLOW and allows a LOT of slippage, even if for a short time while the friction elements fully engage. This will severely overheat the ATF, and if left alone can KILL the seals and friction elements in a few hundred miles.
You are completely safe to change your ATF at this point, just as if it were a new vehicle.
You SHOULD remove ANY "filter" that may have been installed to catch particles from the old trans, AND replace the cooler(s) in the radiator and external. This will ensure no damage is done to the trans by metal particles in the cooler circuit.
'93 F-250 HD, 7.3L IDI, 5spd - FARM TRUCK
I Support: Trailer brakes an every axle over the towing vehicle's GVW; CDLs for RVers; Safety inspections for ALL vehicles and 6 axle trucks (97K GVW proposal).
Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote - Benjamin Franklin
I vote for LIBERTY!