Whirling/out of balance issue??

[trijjicon]

I heard a whirling and felt something was out of balance under my jeep over the weekend. I suspected drive shaft or something. Had a mechanic take a drive with me & he checked rear drive-shaft when we got back to the shop. He stated there was too much play on both ends of the shaft. Will this require a re-build of transfer case ,rear diff, & the shaft itself or??

[Rus Curtis]

I experienced an onset of bad vibration while driving.  Once.  Back then, I neglected the necessary torque needed for the Companion Flange nut that goes on the back of the Output Shaft.  It came loose and spit out lubricant while wobbling real bad. 

I did a road-side fix by using hand tools and was able to drive it home.  I torqued it correctly then.  Have you had the transfer case side Companion Flange off recently?  Done any work on the rear Pinion?

The Companion Flange nut and the Pinion nut on the rear axle, the U-joints on each end the Slip Joint need to be checked.  While I wouldn't initially suspect the transfer case or the differential, who knows?  I would start with those nuts and really closely look at the U joints first.

[athawk11]

Push up and down on the companion flange and the yokes (right where they leave the transfer case and differentials.  If no movement is detected, then the TC and differential bearings are probably okay.  Now do the same up and down test at the slip joints on the drive shafts.  If you notice them to be fairly sloppy, this might be where you're getting the vibration. 

I had a sloppy slip joint on my front drive shaft.  When engaged to spin, it would cause a vibration while coasting at high speeds.

[trijjicon]

I will relay this info on to mechanic. Much appreciate the input.Ty  Ty

[Goggleeye]

I’ve got a similar problem with the sloppy slip joint on the front driveshaft. I presume my only option is to buy a new driveshaft? They seem kind of pricey. Any suggestions on options?