Vibration in square body driveline

[benscharlotte21]

Okay so my buddy just got a 74 Cherokee with axles out of a 87 3/4 ton. It also has a 305 with the turbo 400 tranny and 208 transfer case. So anyways what happens is it will accelerate fine and then when you let off the gas it vibrates like a bastard. Shaking the whole vehicle. I did the front left wheel bearings because they seemed marginal, and also adjusted the right rear brake as I found it was way too right and rubbing. Basically what would possibly cause this? I thought transmission issue maybe? Any input appreciated

 

[marks86]

-replace tires with different set to varify thats not the issue
-put truck on jack stands and put in gear and watch the driveshaft

 

[benscharlotte21]

Tires aren't the issue I had them on my truck prior. We did that and don't see anything but it was night so I'd like to do it gain during the daylight

 

[marks86]

Tires aren't the issue I had them on my truck prior. We did that and don't see anything but it was night so I'd like to do it gain during the daylight

so your pinion angle is good?

also chevy your transfercase/tranny bolts ive had them come loose and case a vibration

 

[benscharlotte21]

Pinion angle is damn near perfect. I was thinking also that I would loosten the tranny mounts and re tighten them to see where it fell back down

 

[marks86]

also what kind of rear end is it in semi or full floater?

 

[benscharlotte21]

Full floating

 

[GreaseDog]

Check you ujoints.

 

[highdesertrange]

grease dog beat me to it. check your ujoints. was the driveshaft balanced when it was cut down? are the pinion bearings tight? these things is what I would look at first. highdesertranger

 

[benscharlotte21]

Apparently, contrary to what I would do, he decided to take it to the shop. They said u joints and bad driveshafts. So 500 bucks later he should be driving this hulk

 

[highdesertrange]

yeah for a 20 buck ujoint. highdesertranger

 

[Greybeard]

Bad driveshaft? LOL! Doubt it. Maybe the slip was removed and when replaced not phased correctly? There is 'supposed' to be a master spline but not always. However, if the truck was ever hung up or high-centered on the driveshaft I guess it could have been dented or bent or had the balance weight(s) scrubbed off. I've driven a 78 GMC with no needle bearings left in one cap and never experienced any vibration, just a lot of noise and worry.