For lack of better knowledge, let's just call it that...E99, 2wd, F250 SuperDuty, Supercab, limited slip .373, 153K easy miles. This was my Dad's garage queen and has hauled a little mulch in the bed or on a light trailer. The truck has never been worked to it's potential. gWhen lightly shaking the truck side to side from above the rear tire areas, after getting a little rythm going, there is a "slop" sound coming from the axle area on either side. I can touch the top of the tire and feel the knocking from whatever is loose. It is the same on both sides. I have not done what seems logical - remove wheel caps and make sure lugs are tight. From what I'm hearing and feeling, I believe it is coming from behind the wheel. I would think pressure would have to come off the wheel to feel loose lug slop. Should there be play in the axle to the point of a knocking noise when shaking the truck?

I also have the rear end shuttering occasionally when making a turn from a stop. I removed and greased the slip yoke with the recommended Ford grease. That did not seem to change anything. I cleaned the splines and filled the splines with grease. Perhaps I didn't use enough...

Thanks for any insights.

 

I don't think you can shake the truck hard enough to make loose wheel bearings rattle with the wheels on the ground, but maybe so. Obviously, check for loose lug nuts. Also, kjack it up and see if there is any play in the whee/hub assembly with the wheel in the air.

The shudder from a turn after stopping may be the rubber isolator going bad in your carrier bearing (support bearing on rear driveshaft). Grab the rear driveshaft at the bearing and try to move it up and down. I replaced my bearing, and this shuddering went away. Unrelated, I also had the stick-slip feeling in the driveshaft, and the genuine Ford spline grease was the only thing that successfully fixed that problem. I bought a small tube on Amazon and they accidentally sent me the 16 oz. can, which was nice.

 

get a large helper,

you lay under the truck and have said large helper do the pushing, locate the loose or worn out thing.

point to check.

ubolts
leaf spring bushings
bearings
lug nuts
driveshaft will not produce slop in the suspension but will produce the shudder or clunk you mention.. but that would be join's or the carrier. you will need to remove the drive shaft to check joints

 

If it has a limited slip differential that could explain the shudder, it might need a shot of friction modifier.

 

Check the leafs too. I had a persistent rattle up front and eventually discovered that one of my leafs was cracked in the sandwich above the axle.

 

Update - for what it's worth, I got this issue resolved at a local gear shop. I took it by a couple weeks ago and they recommended a bearing replacement to fix the issue so I got on the schedule. Yesterday I had both inner and outer rear axle bearings replaced and this solved the slop sound from the side to side movement. As easy of a life this truck has had, I'm a bit surprised to have had this issue but I suppose anything mechanical can / will fail at some point.

 

If the truck was sitting around a lot the bearings were not getting oil on them and that could affect them. Sometimes lack of use is harder on things than regular use.
shawn