Hey all...I suspect my u-joints may be the culprit in my violent shakes when letting off the gas, so I'm curious....whats the best way to check them yourself? Can you tell just by looking?
Thanks in advance!

 

With your truck in gear crawl under there and twist on the driveshaft. You shouldn't feel any kind of movement. You may not even if they are bad but that's about the easiest way to tell if they are really shot.

 

Also try to push the drive shaft in up & down - side to side parallel with the ujoint. If you have any play at all it's shot.

 

I have a lot of play in my Propeller Shaft on my 88 4-Runner as well...The problem I am having with my diagnosis is that the shaft and joints are moving as one piece. The shaft doesn't have play before the joints but seems to have play in the rear dif. Is this still an indication of bad U-joints? I also have much noise when letting off the gas while in gear. THANKS!

 

i would pull the drive shaft off the pinion flange and make sure that the pinion nut is not loose, if its tight, then you probably have a pinion bearing going out

 

Well, I parked my truck on our driveway and set the e-brake and crawled under to check the driveshaft. The only part that moves up and down is where the two driveshafts connect, right in the middle. Is there supposed to be any movement there? There's not much but with enough pressure it moves up an down a little.

 

Thanks Joe. I have read and been told that the pinion nut is preloaded so anything to deal with it would require a certified tech to build it back out if it is adjusted.

Ryan, sorry for breaking in on your post...From my understanding any play at all in that middle joint is sign of considerable wear.

 

I'm hurt but....I'll forgive you hehe. Yeah, I prolly need new U-joints. Perfect timing...right after I buy new Revo's and a locker. doh! :pat:
Such is life.
Thanks for all the replies!