U-Joints

[dcwilkie]

I'm guessing the vibration I'm having (it goes from noticeable to teeth-chattering) is one or more U-Joints. Never having worked on ANY 4 or 6 wheel drive vehicles, I could use some advice for diagnosis and replacement.
TIA,

 

[trog]

Grab each propeller shaft and shake it to find any looseness. Check shaft flange bolts with wrenches to be sure they are tight. Turn all the shafts by hand to see if anything is off-center anywhere.

I am the fourth owner of a CCKW that had one little u-joint needle bearing out of place and stuck under the end of the spider. The u-joint could only have been assembled that way with the force of a press, and it put the shaft off center and out of balance. The previous owner thought the vibration was in the transmission, and took that apart with no success.

 

[WillWagner]

Also, the deuce is good for having the jackshaft, the short shaft between the trans and t-case, bolts come loose. It causes ugly harmonic vibrations and CAN come through the floor. Does your truck have an air shift or sprag t-case? I went thruogh all the drive train and still had a vibration, changed the t-case to an air shift and the vibration stopped...now I have a gear oil leak that I can't make stop , I can live with that!

 

[fasttruck]

Also if any of the shafts were put back in backwards vibration could result; female and of any driveshaft is closest to the source of power if correctly oriented.

 

[dcwilkie]

It's air-shift.
Thanks guys! As soon as the weather gets a little more humidity-challenged, I'll get on it.

 

[dcwilkie]

OK here's the deal.
I squirmed up under the Deuce with my trusty grease gun, gloves and a rag. Starting at the rear drive shaft, I gave it a good shake. It has a little play in it when you twist it, but no up and down play. Next was the shaft between the x-fer case and the middle axle. Same thing. The shaft between the x-fer case and the front may be a problem. I was able to twist it appx. 1 inch. No up and down play though. The short shaft between the transmission and the transfer case has me worried most of all. I can move it up and down a little where it goes inside the transmission. It doesn't seem to be any of the U-Joints, but where the yoke slides into the transmission on the shorty and the yoke going into the front axle.
Hope that makes sense.
I'm sitting here cringing. I bet I need some bearing work in the tranny and in the front diff (shudder).
I greased everything anyway, and it seems to have calmed the vibration down some but not completely.

 

[gimpyrobb]

All of the driveshafts are their own part(they do not go inside anything). Pull the trans tunnel cover and make sure the bolts holding the shft are TIGHT. SHould be no up/down play. If you are saying the output flange is what moves up and down, yes, the output bearing is probably bad.

 

[gringeltaube]

............. I bet I need some bearing work in the tranny and in the front diff (shudder).
...............

YES for replacing the tranny output shaft bearing but not necessarily the pinion bearing.... just pull the bearing retainer and remove one or two of the very thin shims, re-install and check play again, most likely that will solve the problem.

G.

 

[dcwilkie]

YES for replacing the tranny output shaft bearing but not necessarily the pinion bearing.... just pull the bearing retainer and remove one or two of the very thin shims, re-install and check play again, most likely that will solve the problem.

G.

Will I need to pull the tranny or can I do this from inside the cab?
I'm sorry for the dumb questions, but it sure helps to know what I'm getting into.

Thank you again for the great information!

 

[gringeltaube]

.......................... Can i do this from inside the cab?
...................................

yes!