94 dakota 3.9 V-6 Anybody experience vibration when tranny goes into overdrive? I know it's not the U joints because I just replaced them thinking that was the trouble. If it is the overdrive unit, can it be removed for repair without dropping the rest of the transmission? Typically the truck is fine while heading onto a highway ramp until I hit about 50mph and it drops into overdrive. Then the fairly heavy vibe starts and stays until I hit 70mph where it softens. I know this is a boring old thing out there in the big world but it sure as hell would help me a lot to diagnose it. Thanks, Wheelsage

My buddy had a 94 Dak 3.9 4x4 that did the same thing, Cost him $900 some odd dollers to have fixed @ the local Dodge dealer. They said it was the driveline or something to that effect and it needed complete overhaul, carrier bearings, u-joints etc. I thought that was abit much and questioned it myself, but I have a bad feeling I'm gonna find out myself as my 96 3.9 4x2 is doing the same thing. I have an aftermarket extended warrenty. I hope it will cover such odd and costly repairs.. And yes 4 Brand new tires and balancing didnt help

Save yourself a truck load of money and make sure the driveshaft is in balance first. I had a similar vibration to what you described, I replaced alot of parts before balancing the driveshaft worked. Also take a good hard look at your tires for wear, and get the balance checked. Good luck.