1996 tahoe

[DUCOTI]

Hope someone can help!

I have a 1996 Tahoe that after driving on the highway for awhile

give me the check engine light.

When this happens, you get a clunk between 1st and 2nd gears then it shifts normally.

If you stop and shut off the engine for a minute and restart the clunk goes away

and shifts like brand new.

I've brought the truck to my mechanic and he gets no code even though the light is still on, no history either. I brought it to a Chevy dealer (the one my dad retired from as a mechanic) and they found no problems in their check of the transmission and also got no codes to read.

The one time this happened and I got a code by stopping immediately to have it checked read P1345 camshaft to crankshaft position correlation fault.

The guy there said it was probably a sensor.

Any thoughts to help would be welcome.

 

thanks