Well if you've been up to date with a few of my posts you know my O/D's been jumping in and out, 4th to 3rd and 3rd to 4th and so on. I set my TPS and it never really helped. So I've come to the conclusion... Could it be a speed control censor or could there be a wire chaffen somewhere? If so, any suggests where to look? Once I start my truck the lights will surge and in about 10 minutes it'll level itself out and be fine. For example my battery gauge will go down and up, down and up. Could this be a sign of something contributing to the O/D as well? I know my AC clutch went... keep going until it just wobbled free. It's working fine without the A/C now but could this be doing something also? I got the new belt behind my seat to bypass it as a matter of fact. Ah well thats neither here nor there. So lets hear what you guys have to say.

Thanks, Mike

 

Cycling volt guage on startup is normal and a sign youy grid heaters are working. My 93 would drop from normal to 9 volts of so or less for the first 4-5 minutes of warmup. The colder the longer it would take place. check out #1 post on help and it belive its directed at this. Od issues can be caused by the TPS, also there is a temp sensor for the trans fluid that will cause it to drop out of OD if the temp exceeds a set temp of ?? as well if its not warmed up it will prevent it from shifting into OD as "normal" The sensor could be bad. seems the TPS is the biggest issue however.

 

The temp sensor is in the pipe that runs from the driver's side front of the transmission, underneath the bellhousing to the passenger's side of the engine and up to an oil/water heat exchanger about half way up the side of the block. You'll see it there.

Will your cruise control hold constant speed? If not, I would suspect the VSS. It's at the back of the transmission, driver's side, actually on the tailhousing.

 

His cruise is not working at all, at least the last time i was in his truck it didn't.

When he says the lights are dimming , then getting brighter , it is not the grid heaters , it is much more rapid and inconsistent.

 

Somebody could fill in some details here...and I hope I'm not full of beer... There's 2 wires that go to the transmission that supply power for the shift into O/D. I believe it's just a 2 wire weatherpak type connector. All the switching does is take one of those to ground. If you can manually take the right wire (not sure right now which one) to ground, the transmission should go into O/D. This is also what you would do to get O/D if your VSS failed. I can check tonight...but probe those wires, one should have 12V the other is what gets switched to ground. Apply a good ground to that and see how the O/D behaves.

Another idea... Maybe a bad ground? Check ground from battery to body/engine. Some cars, not sure about this truck, have a "main" grounding point underneath the dash somewhere for everything there. I once worked on a blazer that had phantom things working and not working. The girl said everytime she released the parking brake, stuff would start working. The main grounding point for everything inside the car was right there, and the jolt would help make the connection better for a while.