Hey im new here sorry if I don't put this in the right place but I have a 06 3500 lbz with 226,xxx 4 inch turbo back and edge evolution running on level 3 it threw p0700 and p0777 went to fourth let it set a day started it had all gears drove it for a week pulled it in the shop to change the fluid,filters and put in a transgo found no shavings like if it would have slipped the clutches got the transgo in have had the pan off several times and changed to another valve body worked for a half a mile shifted 1-2 went inside left idling for 5 minutes then went from first to fourth. New internal wiring harness no change new tcm no change new ims new change went back to original valve body now have 3rd and reverse along with p0700 p0972 and p0975. Bout ready to build it just wanted to see if anyone has had this happen before.

 

Check to make sure the solenoids are not mixed up an all of the connectors are seated properly

 

It turned out to be a mix of issues from the sticking valve to the wiring harness leaking through to the plug on the back of the trans spent the money and time to get the sonax too and it worked. Every once in awhile I get p2671 it will go to 5th and I can stop and clear codes and runs like a top. Going to put some dielectric grease in the plug on the trans and see if That helps.

 

So did you take it to a shop for them to tell you about the Solenoids sticking or did you check valve body yourself? I’m having the same issue I just replaced the pass through seal the one that’s not suppose to have tranny fluid in and put new tranny fluid in but still pulls the 2671 code for high voltage