overdrive

89 trooper will not go into overdrive, It goes into reverse, it has a normal shift pattern in drive, but no overdrive. I'v checked solenoids each had 13.4 to 14.6 resistance, changed filter and fluid. but when I press the power button are OD shift button nothing.

I have the same problem with my 89 trooper. I've been told overdrive will not engage until engine reaches operating temp. I've placed cardboard over my radiator for a short time and coaxed the overdrive to engage (be careful), but I don't like this and still have not found the problem. If you know please let on.

Sounds like one of your temperature sensors. At least in some vintage of Troopers there is one for the dash gauge and one for the computer. The dash can read fine but if the other one is shot the AT won't go into OD.