Murphy strikes again. I have to travel in the morning, and on the way home tonight the check engine light came on at a stop light. I noticed it was alittle doggier pulling away from the light and it never shifted. 45 MPH=2600RPM. Also noticed gear indicator does not highlight 2nd or Drive. Tried to manually upshift and downshift no response. Stuck in 2nd gear in all forward gears. Park, Reverse and neutral all work OK. Fluid is fine, temps were OK.

2002 2500HD D-Max Allison Crew Cab Bone Stock.

Suggestions, comments? THANKS!

NSBU switch. Easy fix if they have one locally. Is covered under the 100,000 mile emission warranty. Common problem.

Read the thread in this section about loosing transmission lights, it covers this same problem.

Thanks! Local Indy area dealers want approx $175-$200 for the NSBU. Heavy truck dealer has it in stock for $80. Go figure.....

BTW, THANKS again!

Well, let's try this again. I replaced the NSBU and now have all the indicator lights working on the gear selector, but the "Check engine" light is still on and the test drive still stuck in 2nd. Where'd I go wrong?

OK. Pulled the 25 Amp backup light fuse, reinstalled, and it cleared the check engine light. Shifts fine. All is well with the world.:)