Anyone had this problem?

greenskeeper

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So took it out for a short drive today and the vibration still exists. What's the next area of focus?

Did you check the t-case output flange for radial and in/out play? If that large nut holding the flange on gets loose it can cause a vibration.....the torque on that nut is something like 150 ft/lbs I think (?)

Flat spotted tires could also be the issue if you hardly drive the truck.
 

Desertfireguy

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Vibration occurs at about 50 and 75mph. Increases frequency between 75 and 80 which I don't do for long. I replaced all 3 rear u-joints, but it still persists. I'm beginning to think the bearing behind the differential yokes are going out since there is a little play on both ends. Also, when I boletd back up the driveshaft, the rearmost ujoint has some play side to side within the clips, but fits the driveshaft perfectly. Does the yoke require different sized caps from the driveshaft?
 

Clb

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If someone swapped an oddball axle, into the truck (one not made for the idi) you may have the series of ujoint mismatched.

That sounds like an issue, (caps not fitting tight).
Yokes and trunnion caps should be a tight \solid fit.
 

Desertfireguy

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Awesome. Sounds like I get to do more research/work. Do you think changing the yoke would be easier than swapping the axle? I'm guessing if all this stuff is squirrely, it might be time for a complete driveline rebuild. Either that, or someone on here can hand me $6K and make it their problem! :smoke:
 

Clb

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Depends
Verify the problem first.
Got pics of issue?
Redoing a driveline and yoke on the truck is half the work of an axle swap.

edit
are you saying" the cross has play side to side in the clips " to read
looking down the length of the truck,
That the u joint will move left and right (wheel to wheel) inside the yoke on the diff?
If so that's an issue that'd cause a shake!
 
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Desertfireguy

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So I kept tinkering and double checked both pinyon nuts and they were pretty loose. Vibration went down pretty well. May need a rebuild eventually, but I'm going to get a few more miles out of it. Also put 3 more pumps of grease in the rear ujoint and that play reduced as well.
 
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