rear end slack question

[knoxemt1983]

well, I have had this ongoing problem with a bad vibration between 15-55 mph, and a bad clunk when letting off then back on the gas, and really loud clunk going into reverse or into drive. My question is, how much slack should there be in the rear end? I put the truck in neutral, and twisted the driveshaft to see if I could see any play in the u-joints, and I noticed about an inch of slack in the rear end. Hopefully this in not too far out of the normal, it seems to me like it is more than it should be though. Thanks in advance for any info or advice you can give me.

[bigcountrysg]

With out actually measuring it that sounds about right. I would inspect those u-joints. If your getting a clunk when you let off and get back on the throttle, that is a sign of the u-joints being bad. If you have bad u-joints you will have the syptoms you are describing. How many miles are on the truck. Have the U-joints ever been replaced. If not at 13 dollars a piece I would replace them. The aftermarket ones are greaseable. Stock ones are not.

[mrnecsteve]

I agree, typically a ujoint fails on one bearing cap first ..before it fails on both caps. When one cap is bad ,its tough to detect with hand force alone. Its probably the one closest to the trans.

[knoxemt1983]

I got the u-joints today and aam about to replace them. yeah at 13 bucks a peice I figure I might as well replace them. sorry about forgetting the specs, it is an 03 F350 4x4, 6.0l, with 80,000, and chipped since new. Thanks for the help, I will let ya know what the results of the u-joints are

[knoxemt1983]

well, I changed all the rear shaft u-joints and the problems are gone. Thanks for all the help. The fron two were in good shape, just changed them while I was under it. The rear most u-joint was bad, two of the caps were mostly broken off and gone and the end if the u-joint on the driveshaft side had worn down into a cone-like shape.

[bigcountrysg]

Glad you got it fixed, glad I could help you out.