biker55

Hi folks, this is a continuing problem that I've had since I had my clutched replaced at the dealership. I have a vibration at about 40-50 mph and at 70mph. I brought the truck back to the dealership and they changed the the rear u joint which lessened the vibration but is still noticable. I asked if the mechanic balanced the shaft and the service manager chuckled, saying that they don't have a balancing machine and that it would have to be sent out. now the service manager is telling me that I need a new front driveshaft. I got under the veh. and was able to rotate the driveshaft about 3/4 of a turn and the front I was able to move up and down about 1/2 inch but not the rear part. how can I tell if it's the driveshaft and not the u joint? a friend of mine says that drive shafts rarely go bad. thanks

workinman

is it at the same rpm's when it occurs if not it could just be tires out of whack. repacking your wheel bearings might help my truck would ride rough around 70 until i repacked front bearings. have you checked harmonic balancer mine went out recently the outter pulley completely separated from inner half of it they do come loose. i dont know much about drive shafts but it seems like a 3/4 turn is excessive. no big dings in it that would throw off balance? any cel? make sure bulb isnt burned out it turns on w/ koeo. hope this is somewhat helpful for you.

biker55

thanks for responding. I don't have a harmonic balancer on the driveshaft. and the vibration occurs at around 40-50mph and at 70mph. lately I've been hearing a subtle knocking when I decelerate to 10mph. thanks again.

workinman

i would hope you dont have one on drive shaft. the crankshaft damper would have been a better term for me to use. unless your positive its in the driveline/suspension. then im not very useful unfortunately i know more about computers and external engine than driveline/chasis. but i know if its at the same rpms it is usually a drive shaft but if only at high speeds im gonna guess wheel bearings they are pretty easy fix pull grease cap off and work in new grease deep in bearings fill cap with grease and pop it back on mine sounded like the old cop cars when people would put rocks in hubcaps to here em comin. maybe tie rod ends theyve been known to "click" if you jack up truck off ground and grab tire can you rock it side to side up and down . shouldnt be able to at least not much. unusual tire wear. tranny has fluid. differential leaking at all. brakes arent grabbing. if you have abs a sensor could be at fault.wherever you bought your tires ought to balance em for you for free . i would think. hopefully someone with more knowledge on the subject will jump in and post but i know how hard it can be to get a response sometimes.do you have auto/manual 2 wheel or 4 wheel. good luck.

biker55

thanks for the response. will wait until this heatwave cools down a little before tampering with the truck.

workinman

smart move.