2000 F250 4R100 Trans Issue
2000 F250, 7.3L, 4R100 trans. 100k miles. Previous owner only drove it to tow a 5th wheel once or twice per year. So it sat a lot.
Truck does great in cooler temps. I live at about 9,000' elevation, so the weather is cooler than in Denver. Most of the time the trans seems to be fine but after driving in hot weather (90 degrees or hotter) it starts to act up.
I drove from Frisco (cooler temps) to Denver, where it was 96 degrees. The truck drove great, no issues until I stopped. I backed up about 40' but when I shifted back into Drive, nothing engaged. The RPMs went up but no movement. I shifted to 1st and the truck went forward like normal. I kept accelerating and manually shifting into 2nd and eventually Drive. Once in Drive, the truck drove/shifted normal. Once the truck cools down, it shifts like nothing happened.
This scenario has happened 4 times; all on a hot day, all immediately after an hour or so drive and all after backing up. I've never noticed a time when the trans acted up without backing up first.
So far, I've only replaced the trans fluid/filter even though the fluid looked pink and in good condition.
Any ideas?







