A Quad Cab lifted 4X4 SLT w/360.
Has 68000 miles, and once it hits around 1800 RPM, at times it will kick out of overdrive briefly. You can see the tach jump a couple hundred RPM, than go back down. Never fully engages into a lower gear, just won't lock into Overdrive. My mechanic adjusted a Throttle something???. That seemed to take care of it for about a day, then started doing it again.

Any one else have this problem? The tranny was just serviced about 300 miles ago, and it was doing it before that.

 

ive been having the same problem...

however mine seems a bit worse...


at around 2nd gear, the trans will not shift into third till around 3,000rpms or if i let off th egas a bit for it to shift, then when i reapply pressure to the gas if the speed is under 35mph it will drop back to 2nd till the rpms are over 3k.. sometimes it wont engauge till 4k rpms.

from what ive read the problem is the transmission control computer or the torque converter clutch... havent found a way to replace it or a cheap place to get the parts... so im still sorta trying to figure it out...

 

My friend has a '99 Diesel wiath the same problem. He said that they did what you suggested in changing the computer, but mine isn't throwing a code......?? Not sure if his was either though.