K, I know there are several threads on this. Maybe one reason I am stumped. My kids blazer does this about twice a week. When it does this he unhooks the battery for 5 min and it runs fine. I have read everything from ignition switch, switch solenoids, ecm, connector on the the transmission. We have checked that, and it looks ok. is there anyway we can test this stuff to narrow it down. Im not one to just start replacing parts, He is auto tech at school and his teacher is telling him its the torque converter clutch circuit.

Thanks for any insight

 

I got a question for u .. when it happen did the anti brake light come on and did the speedometer go too zero?

 

I had a problem if when I didn't give the truck a lot of gas and kept the rpms high the speedometer when to zero and the engine light came on, causing it to not shift. I don't remember the exact spot but there is a speed sensor and that can cause a problem. Thought I should share this. Hope it helps.