ol' 93 12 valve

My 91.5 auto isnt shifting into overdrive. I thought it was a low voltage problem because i wasnt sure the truck was charging but i checked it and its charging at about 14.5? What are things to check for.

I need my truck back on the road by thursday night have a 5 hour drive to make. Any help is appreciated

thanks

Tuckerdee

Is your speedometer and odometer working. If the Vehicle speed sensor isn't working, then the OD won't work either.

ol' 93 12 valve

yah there both working. the last time i drove the truck it felt like it would kick into overdrive going down hill with just the slightest throttle but then kick back out.

Tuckerdee

Then it sounds like your throttle position sensor needs adjusting. There's a procedure in the sticky section for doing this. The issue of the TPS is why many auto guys have changed over to the in-cab potentiometer...also in the stickies.

wannadiesel

You may find this thread helpful.

https://www.dieseltruckresource.com/...d.php?t=211628

Read carefully, as it discusses both '91.5's like yours as well as the later trucks.

ol' 93 12 valve

I already have the potentiometer.

ol' 93 12 valve

Figured out the problem. The battery was draining its self. I put a volt meter on it and the battery was losing volts. It was one i bought from autozone, i put a good battery in it and did the same test with the battery termanls on the battery and it didnt drop any took it for a test drive and overdrive worked.