2006 2500 dodge 4x4. At times seems the truck starts in 2nd or 3rd and will not shift out of. turns about 2800 rpm at 50mph. Can turn ignition off restart and most of time will shift fine until happens again can be weeks or days between events.

Any idea what the problem could be?

 

There are 2 solenoids in right front corner of tran, in pan. They go bad.
this might be your problem.

 

Change out the soleniods do the GM upgrade!

 

Alright im new to the whole diesel scene. never had one before and just bought a 2004.5 dodge 2500 in feb. got called out on the damn diesel burnout challenge yesterday and went to do it. put the truck in gear, tried to power brake and it wouldnt go passed 2000rpm and wouldnt build past 15psi. Any suggestions as to what happened? 2004.5 dodge 5" TB edge juice with attitude AFE intake

 

Really good brakes! Practice makes perfect try it on wet or sandy road first. 15psi is plenty to snap a input shaft consider yourself lucky!