U-joint Problem

[kdorminy]

I have recently started noticing a knocking sound whenever I let off the gas (not accelerating) going at fairly slow to slow speeds (especially when coming to a stop). After investigating, I have found about 1\32" of play on the rear u-joint when I apply upward\downward force, not in the rotating motion of the drive shaft. I had the u-joints replaced less than a year ago with new ones with grease fittings. I tried to get some grease in there, but the location of the fitting is inaccessible without taking it apart. (VERY POOR DESIGN!). My question is would lack of grease cause this problem, or is it something more serious? Also, I DO have a fair amount of play which I believe is between the rear differential and the drive shaft that occurs after coasting and accelerating and shifting between forward and reverse which could be possibly be putting the joint under excessive stress. After looking up on it, I have found it to be quite a common problem and in my model truck. Even the factory statement to the dealership explains it to be normal. Anyways....any help would be greatly appreciated!

[Impalacat]

Do you have a vibration while running down the road? maybe the slop you feel is the from the rear end and not the u-joint, they do make a needle that goes on the end of your grease gun that you should be able to get in there with.

[spartus]

Change the rear joint again, its SHOT. Greaseable joints are WEAKER than solid OEM joints. Go get some OEM or SPICER joints and put those in. You can generally get 100k+ out of a greased for life joint.

[Zembonez]

It does sound like the joint failed. Some aftermarket brands do not last very long. The Chinese made ones are cast out of pretty cheap metal. I'd go with an OEM or at least a good USA made joint to replace it. Like the above poeter said... the greased for life joints are just fine. There really isn't anywhere for the grease to go unless the joint fails.