Don't know much about my tranny, but it does not shift into overdrive in the mornings, have had a lot of repairs done to fix the problem, did a full tranny flush, and replaced all the filters and stuff, did the throttle linkage replaced, the TPS replaced, and the Crankshaft sensor replaced. I guess my question is that would the PCM sensor be causing the problem with the overdrive?? Help me out here!!!

 

Sounds normal to me.
The tranny temp sensor will not allow OD until the fluid temp reaches 70F.
If it seems like it's taking too long to get up to temp perhaps the temp sensor is bad.

 

What year is your truck ... First I would throw it on a scanner and see if anything pops up ...could be a temp sensor if it is 95 and up ...You can scan it , if its a good scanner you can drive the truck and see if a all the soleniods are working ...go from there !
Good luck

Greg

 

Hook up a scanner to the truck and check to see that the comp is sending the od singnal to the trans. If it is sending the signal to the trans, then I want you to check two other things in this order. There is a solenoid pack on the vb that controls od and lock up, check to make sure those are in working order( you need a wiring diag. for your truck to ground the soleniods. The wires are located in a plug going into the trans vb just aft of the shift selector.) If the solenoids are working. Get a pressure gauge and hook it up to the od test port(located on the drivers side of the trans to rear between the trans and the od unit toward the top) and see if you have or are loosing pressure. Make sure to use a guage with 200 psi capability. With that tranny flush and and fact that it does not work in the morning are signs of a bad seal in the trans(4th gear piston support seal). Let us know.


Richard

 

thanks guys you are lots of help, it is a 97 just for your info info greg

 

I think this seal is what's wrong with my 97. Does the whole trans need to be pulled apart or is it accesible at the vb?
Thanks

 

The seal is two parts and is part of the 4th gear piston/support. The rear(overdrive unit) has to be removed to access the seal, not the vb. Any trans shop shold be able to do it but before you do that...attach a pressure gauge to the od port on the trans as I posted earlier and see what pressure your getting first (you should see from 75-140 psi depending on throttle position).


Richard