This is my first post so bear with me. I have a 2005 durmax SLT 2500HD I have about 9,000 miles on it now. I got it 10/4/04. I was going down a hill at 35 miles an hour. When I got to the bottom and started up the hill it missed and bucked and the transmission went in to neutral. I put it into gear and pulled to the side of the road.I called Onstar for a check. It took about 20 seconds and they said that I had trouble in the transmission and to take it to the dealer in 3 days. The engine light came on also. When I took it to the dealer they put it on teck 2 and got codes po500,po700 and po 776. The engine light had gone off before I got to the dealer. The truck was running fine, no problems. They called GM and I called them also. GM Tecks and dealer are going to work on it It is at the dealers now. I was wondering if any Tecks on this forum would know any thing about this. When I find out what they found I will post it on this site. Thanks for any help you can give. Carl L.

Well I got the truck back from the dealer and they couldn't find anything wrong. They hooked up a VDM (I think that what it is called). Anyway if anything happens to the transmission it has a button that I press to take picture's of what is happening. They said this might be a one time thing. I hope so. How about the Tecks out there, what do you think? Carl L.

UPDATE: GM called me today and wanted to know how the truck was doing. They said they would call once a week for the next 3 weeks. They are really trying to help. The paper work from the dealer about the codes are;
Code po500 PCM ( VSS ) Circuit
Code po700 ( TMC ) reguested Mil Illumination
Code po776 Pressure Solenoid B controlled Clutch Stuck off
My truck is stock nothing added. Carl L.