I have a 06 3500 5.9 with an automatic. it is stuck in 2nd gear. I have had the gov solenoid changed and many other diagnostic things done the shop says its the ECM. Is this something that only can be fixed by the dealer? I have heard conflicting reports that the dealer is the only one the can flash a ECM? What is my best option?

 

The ECM has nothing to do with shifting at that point. Need to do some more research to see why they think it is stuck in 2nd gear, they generally don't just do that unless there is a mechaincal problem.