I have a 96 Tahoe 4 x 4. 265K miles Had new transmssion 80K ago.

When just started this tahoe runs great, no problems. When it getshot you will be driving along and it will seem like the transmission has been dropped into nuetral...if you pull the shifter down to 2nd you can travel along but if you shift back uo to 3rd it will be in nuetral again. If you stop and shut the ar off for 10-15 minutes it will return to normal but then quickly develope the problem again if it gets hot. If I want to make it happen I just need to get on the interstate and run 70 for less than ten minutes.

I think it is temperature related but is there a chance I'm getting air in the tramsmission fluid somehow and it is foaming when it thins out with heat ?

 

No foaming is is not when it thins out from heat that happens when the fluid level is too high or too low. Check your fluid level make sure it is at the proper level and it sounds like you may be due for another transmission. Also check with your local dealer because the 96 trucks had a problem with the PCM and there is a new one and also an update that can be done to prevent problems with the electrical part of the trans. Also unless you drive this vehicle on the freeway or highway all the time any intown driving should be done in 3 this keeps the fluid flowing fast enough to cool the trans properly

 

Jchevguy replied to investigate the PCM....is this the Power Control Module ? It may be this as it seems that the dashboard gets wacky at the same time the transmission seems to go into nuetral. Is there a tchnical bulliten site for GM where you can search this topic ?

If I take this truck to the local dealer it will be $900 and a bunch of pressure to give up on it and get a new one

Thanks for the advise jchevguy

 

Two things: (1) Get the codes checked to see if there is a tranny code stored. Don't know about a '96 OBD-II, but my OBD-I '94 will store tranny codes without lighting the check engine light. (2) Have your charging system checked to make sure you are getting sufficient alternator output. Low voltage will often affect shifting, although I don't know that the tranny going into "neutral" is a symptom of that. My experience with that is that you have one gear, 2nd, rather than losing everything.

I had a problem very much like yours a couple of years ago
that turned out to be a wiring job. Don't know specifically because I had my favorite tranny shop on it, but they ended up cutting/splicing/replacing some of the external tranny wiring and/or connectors. Hadn't heard about the PCM issue, but it would make sense.

 

What happened to your Trans? Mine does the same thing, finally went out, rebuilt less than 1000 miles and still shifts hard into 2nd from 1st. Whats the damn problem?

Thank you.

 

He still has the problrm but recently read that it's an ignition signal problem and both the ingnition switch and a wiring harness must be cjhanged at the same time...if you believe that.

 

Hey, Im having the same tranny problem, When cold it drives fine. once it heats up, it slips between shifts. In addition I hear a rattle noise once i hit 2000 rpm and in between shifts. Once it get to normal running temp. the rattle noise in now at all times. even in park and neutral. at this point the truck does not move at all. but If I shut it off, then start it again it will move with the loud rattle noise. any sug.