Well just a few questions. I had the 4l80e tranny rebuilt in my truck, it worked great for a bit. Then it would shift into o.d. and lockup, but not come out of lock up or o.d. when you shift to third. Brought it back to the tranny shop, he said he doesn't know the problem, thought it might be the neutral switch on the outside, so i changed it , not a big deal. Still had the trouble. But then it started working great!.. O.K. tranny tech said "well if it is working fine, drive it." Well now it shifts thru all the gears and into o.d., but now the lock-up doesn't engage. Tranny fluid is clean and no burnt smell. No metal in it either. I have red that the converters can fail easy on these tranny's. It is going back to the shop for warrenty work, but would like to hear if yall have had the same happen?? Thanks for all the input!!!

 

sounds like either the converter or the lock up solinoid valve is hanging in the valve body

 

Check your voltage before you throw more money at it. It won't lockup with low voltage, sometimes won't even shift into OD.

 

Those two are what I am thinking. The tranny rebuild is still under warrenty so if either of those are bad i won't be stuck with the bill. I hope that it is the lock-up sol. then it can be remedy'd in the truck.

 

well, turns out it is not the converter or solinoids. the tranny tech says it is computer related. with his scanner tool says engine temp normal 190deg , then the tranny end it says the tranny temp is 41 deg below zero! i did some research online and various people have commented on this black box control module inside. they say it has control switches and sensers of sorts. more specifically a tranny temp senser. any coments experience??? many thanks again!!!