where is the overdrive switch on a 1991 GMC sierra 4x4?

[playersolidrock]

I have a 1991 GMC Sierra 4x4 pickup,and my overdrive is sticking,and I was wondering how to turn it off.any advice is appreciated.

 

[hangtrojanover]

Shift to drive instead of the overdrive, O with a D in the middle of it.

 

[Molson02536]

I have a 1991 GMC Sierra 4x4 pickup,and my overdrive is sticking,and I was wondering how to turn it off.any advice is appreciated.

Your OD is actually the the torque converter clutch locked in place, if your TCC always locked: TCC apply solenoid circuit shorted to ground, TCC solenoid blockage (easy fix in pan), or TC broken (must remove trans and replace TC). keep in mind that running the transmission on the hyway without the TCC locked up will heat up the transmission fluid and can cause transmission failure. Good luck and hope this helps, you can always try adding some transmission fluid additives to help clean the transmission fluid before you service it. "transmission fluid conditioner, not the stop leak"