Out of nowhere my overdrive does not work. the light goes out on dash when button is pressed, shifts out of fourth but finds nothing in fifth. just revs up until I take the overdrive off again to put it into fourth. I'm pretty familiar with the trans. I have not done any pressure tests yet so i don't have those numbers. I believe the clutches are good because all other gears work and shift great, which 5th uses the same clutches as the others. THe only Simple **** i can think of is the OD solenoid is not opening and the UD is closing leaving me with revving until i take off OD and reopen the UD solenoid, putting me back into 4th. could it be as simple as the stupid OD button not functioning properly? No DTC's either which is my monkey wrench. should of thrown one if slenoid was malfunctioning, right? anywhoo, 52000 miles on it, babied,babied, babied. all this power and i drive it like its a caddy. Tranny and truck is in superior condition. I'd admit if i whooped on it, I need to get this fixed. any intelligent help would be greatly appreciated. Oh yeah, before 20 people ask, YES, I CHECKED THE FLUID.

 

How many miles you have on your fluid? Ever done a screen change? I would start there and it sounds like a valve body solonoid is sticking?
Also,
I would check into this TSB TSB #2101505 It's a delayed engagement due to a cooler return filter replacement.

I found this maybe it can help http://www.scribd.com/doc/7095618/54...mission-Manual