I have a 2006 2500 HD Crew Cab with the LBZ and I was driving today in stop and go traffic when I felt a shudder and the tranny wouldn't shift anymore and the check engine light was on. Pulled over put it in park andthe tranny shifted to first and now it's stuck in first. I don't have any engine mods. The only thing I have on the truck is a set of 285 75/16 and a 4 inch cat back exhaust. What could it be?

get the codes from the tcm.

Fill out a signature with the mods you have.

Welcome to the site.

My o3 did the same exact thing today, on a back country road, going down hill and slowing down. I felt that shudder also. It didnt shift, and when I shut it off, restarted it, it didnt shift out of first 20 miles all the way home. The dtc codes I pulled are PO748 Pressure control solenoid A, and DTC PO700 transmission control system(mil request) Whatever that means. I have 98200 miles on the bugger, so monday morning I am callin my cousin who is a service manager at Ewald Chevrolet and get this fixed pronto. I will post the results here when we get that far!

Well took my truck into the dealer and there was a selinoid that went out. It has been at the dealer since Thursday waiting on parts. Hopefully get it back tomorrow.