Need help diagnosing vibration
Diesel Wrench
Joined: Sep 2009
Posts: 574
Likes: 28
From: Torrington CT
An out of time driveshaft can only happen to a two (or more) peice drive shaft. The u-joints have to be in the same position from front to back, in other words the caps have to be horizontal and vertical from front to back. If they do not line up there is prob 90 percent chance you will get a vibration. Ive seen drive shaft shops send reman shafts back to customers out of line, think they are creating fun by doing that I guess.
BOMBARDIER
Joined: Jul 2007
Posts: 12,809
Likes: 668
From: Billlings, MT
Vibration started about 5 months ago. Last repair I had done before that was new rear brake calipers.
Vibration only occurs at speeds over 55mph, most pronounced between 65-70. The dash rattles, floorboard vibrates, etc. It's felt all over.
Things I have done with no resolve:
new tires
removed front drive shaft and drove
replaced both U joints on rear drive shaft.(the said it was balanced but I don't know that they had the equipment to do it?)
If you left off the gas and coast at 750rpm's, the vibration remains so I don't think it's related to the engine. The vibration feels the same speed as the drive train. If you hold on to the 4x4 shifter, you can feel the vibration there.
I just don't know what else would be vibrating? I suppose I could remove the rear shaft and drive it to see what happens.
Any advice?
thanks,
Vibration only occurs at speeds over 55mph, most pronounced between 65-70. The dash rattles, floorboard vibrates, etc. It's felt all over.
Things I have done with no resolve:
new tires
removed front drive shaft and drove
replaced both U joints on rear drive shaft.(the said it was balanced but I don't know that they had the equipment to do it?)
If you left off the gas and coast at 750rpm's, the vibration remains so I don't think it's related to the engine. The vibration feels the same speed as the drive train. If you hold on to the 4x4 shifter, you can feel the vibration there.
I just don't know what else would be vibrating? I suppose I could remove the rear shaft and drive it to see what happens.
Any advice?
thanks,
Diesel Fan
Joined: Apr 2009
Posts: 59
Likes: 2
From: Phoenix, AZ
Dieseldanboy, now ya lost me....if your driveline is in time and its a single peice driveshaft then the vibration is not from the driveline being out of time. I dont know how you could get a single peice shaft out of time without twisting it or cutting and welding. Could be bent, u-joints, out of balance, loose,etc. Im fried. So it is true right?!?
Diesel Wrench
Joined: Aug 2009
Posts: 803
Likes: 47
From: hopewell pa
i worked for a guy this summer who had a big truck that had the same problem when i told my boss bout it he told me to run er till somethin breaks then we will know what the problem is. so that is my advice to you may not be what you want to hear tho 
Diesel Wrench
Joined: Sep 2009
Posts: 574
Likes: 28
From: Torrington CT
i would have someone help you with this. get all four wheels in the air and get underneath the truck. have someone put the truck in drive while you move the 4x4 linkage from underneath and see what happens. 
