With gear selector in "D" the truck moves off like it's in 3rd gear so I tried shifting to "1" and transmission locked up. I found that if I shifted from "P" to 1st I can shift transmission manually, but if I try to get into 1st any other way the tranny locks up. Someone said maybe a voltage problem or bad transducer. Where is this transducer? Any other ideas? Thanks.

 

A bad ground and/or bad batteries can cause trans issues. Certainly worth checking into making sure terminals are clean, brain box is grounded good, and batteries are good. Not sure about this issue though. How does the fluid level and condition look?

 

It is fixed! Thanks to Bill Kondolay at DTT, who successfully troubleshot the problem over the phone down to the overdrive solenoid (MOPAR 52118500)

I can not say enough good things about the folks at DTT. I bought and installed this tranny almost 3 years ago and when I called them for help you'd think I was the only customer they had. Always put me through to Bill--I called him somethng like 6 times today to ask him questions while I was working on the truck. I'd taken the truck to a local shop who scanned the codes and told me there must be a crossover leak somewhere, most likely a bad overdrive. Bill said "NO WAY" and thank's to him and his team I fixed the truck for only $120 and it runs like new.

If you need a automatic transmission for a "bombed" truck I don't think you can do better than DTT!

 

I had a feeling what I said wouldn't be it. Oh well. It never hurts to check simple things to be sure.