I was getting a shutter from the rear end a month ago on my 97 f150 4wd auto. I changed the rear driveshaft ujoints and completely changed out the rear diff fluid. The slight shutter in the rear did not go away. The shutter was only over 58MPH. Tonight the rear drive shaft's rear ujoint broke going 65MPH. Anyone have a clue as to what is buggin my truck? I welcome any and all ideas!

 

i would crawl under the truck and try to turn the pinion shaft on front of the differential. should only move back and forth about 1/8 inch or less. if you have much more, then you got worn bearings or gears inside causing the shudder. if all that is o.k., i would jack up each wheel individually and try to wiggle it up and down and chekc the axle bearing by the tire. if you got the little axle, the inner race is actually the axle shaft and does wear out over time, and high miles.

 

Hi and welcome to FTE

Any chance the driveshaft is bent? If so it will be out of balance and that's hard on the u-joints and can give you a vibration.

 

Not sure. How would you check. I hadn't done anything recently to stress it, ie. towing, pulling, hole shots.

 

I would take the shaft to a machine shop that does driveshaft work and have them check it.

 

The broken ujoint has caused the driveshaft to break, they found where one of the weights was almost off. Also the driveshaft when breaking broke the tail assembly to the transfer case. RESULT: The Ford dealership that repaired the truck will have a christmas party now thanks to my $1100.00 repair bill. However the shutter is completely gone. I would have to say that those of you that suggested problems with the driveshaft were correct. Wish I would have come on this site $1100.00 ago. Will in the future. Thanks All!