Rear end problems

[halo1111]

Searching the forum for a while now and appreciate all the help but this one has me stumped. 1999 Ford Exp 100K + miles.....

I have a rear end clunk/knock usually while coasting and sometimes going up hills. Seems like when I let off the gas and coast, the rear end starts knocking/kcking and the car feels like it's slightly jumping.

Changed out the rear diff fluid - no wear found and refilled - still knocking/clunking ----- One poster said it's the ujoints. dropped the rear shaft and changed out the front/rear ujoints - no wear on the original but changed them out since I already had it off - still the same problem.

Finally decided to put the rear end up on jacks and put car in drive. Noticed the rear shaft is jumping back and forth and the tires are jumping/moving as well. Hard to explain but there is a lot of jumping in the rear. I was afraid to get out and look thinking it was going to jump right off the jacks....

Any ideas help greatly appreciated!!!

Dave PA

 

[halo1111]

Anybody? I know someone out there can help???

Tried lookng it over again and it seems to be a problem where the rear wheels are trying to catch up and are skipping when the shaft moves

 

[yavapaires]

Anybody? I know someone out there can help???

Tried lookng it over again and it seems to be a problem where the rear wheels are trying to catch up and are skipping when the shaft moves

Sounds to me like a couple broken teeth on the pinion gear. But, you sais you pulled the cover, and found nothing wrong. Did you spin the gears around? Gotta be a broken tooth or more in there somewhere. Check ALL the gears, ring, pinion, side, and spider. If you have traction Lok, be sure the clutches are not chewed up.

 

[gavin]

possibly the slip-joint needs greased?
chock the tires and put transmission in neutral.
check for rotational play at the slipshaft

 

[halo1111]

Thanks - I'll give the spline a look and then drop the diff cover and give it a closer inspection.....