Shifting just fine and then gets stuck in 1st gear. Help!

[Retiredwarhorses]

While that is true, if you are in limp mode and there is no light you would immediately suspect the TCM has no power.

again…No, that’s not the case, you can have major issues and no lamp, and only flashing DTC’s reveals the issue.
but hey…working on them 7 days a weeks, wudda I know.

 

[GuntherRommel]

I would try to find someone with a Super Flow automatic transmission tester. You can over ride the TCM and diagnose most problems. We have one and use it on every rig. You can find them on cbay or gov planet. Plus its fun shifting from the passenger seat