I am the proud owner of a 93 Dodge Ram 250 Diesel truck. The power control module was gone on it when I bought the truck. I had no speedometer and no overdrive. I replaced the PCM with a remanufactured unit bought from HUNT Chrysler Plymouth in Milton Ont. in Dec.2006. When this unit did not correct the problem, I returned it and they ordered me another one . When the check engine light was on the speedometer worked as did the overdrive, with the new unit installed. The original one was a A56029103 and the two remans were R4746568. When the second one was installed I got the same thing happening. I took the truck into Hunts and the mechanic there did a diagnostics on it for 5 hours plus and came to the conclusion the PCM's being supplied were faulty. He proceeded to call Chrysler and requested taht one be pulled off the shelf and bench tested. Chryslers response was that we needed to replace the crankshaft speed sensor. One was ordered and i received a call two weeks ago that the part was in. When I returned to have it replaced, they had received one for a gas job. They ordered another one and I had it installed on Monday, July 16,2007. When the mechanic did the road test again, nothing changed wit the new crankshaft speed sensor. The mechanic feels Chrysler is supplying faulty PCM modules.When he did the diagnostics in Dec, when he forced the check engine light to come on the speedometer worked fine. When he road tested it this week if he slipped the truck into neutral and shut the truck off and turned the ignition switch on the speedometer worked. When we tried a PCM from a gas truck the speedometer started right away in December but of course was not accurate at all, nor would it control other functions. We have done everything Chrysler has suggested. I have now spent around a thousand dollars for what the mechanic feels is a defective part being supplied by Chyrsler. I need your help please. I realize he truck is well out of warranty, but at ta minimum need a module bench tested. There is a company here that will bench test this one, and again will cost em another $80.00 to have it tested. Your suggestions and thoughts please! Any help is welcome.