Rear Shaft Vibration W/New Joints

[juniorwatson]

I've got a 1998 Tahoe 4WD W/Electronic shifting transfer case.

The truck had a vibration Tuesday going into work noticeable from 40 and very noticeable at 55, so I turned around and came home and pulled the rear driveshaft.

I found that the rear U-joint had a grinding feel to it in the yoke of the shaft, but not sloppy.

I then put the truck in 4WD, and drove a mile or so with the front shaft. There were no vibrations whatsoever.

I replaced both U-joints in the rear shaft, and reinstalled last night. The vibration is still there.

So now I'm wondering if it could be the extension housing bushing, for the driveshaft yoke (P/N: 15665313; ITEM: 3)

I've had to replace these on my M22 4-Speed, and my 9C1's 4L60E before.

The image above is what I got from my GM Parts guy in Austin (using my VIN), BUT my transfer case is different that this. Mine does not have a removable item #4 (Like the 4L60E).

Some of the oil leak you see pictured is from a seal with 93,000 miles on her, and some is from having the shaft out while driving in 4WD with the FT only to try and pin down the vibration. I have a new seal and Auto Trak fluid to do that this weekend.

It looks like I'd have to separate the transfer case in half to replace the bushing.

I'm wondering:

1. If anyone has pulled these apart, and it it's as easy as I'm hoping.
2. Any other thoughts on what the vibration could be? I would think a bearing would make noise, and I'm not experiencing that.

Thanks!

 

[BattelWagun]

The actual rear driveshaft itself could be out of balance, but there isn't really a way you can check that yourself for sure. Seems like it though as when you took it off the vibration went away. Also, did you replace both u-joints? The other may be causing a problem too. As for the transfer case, it can be done I think, just take your time and be careful.

Edit: disregard my u-joint question...


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[juniorwatson]

Just got an updated exploded assembly dwg from my guy. Looks doable.

I'm gonna speak to a local garage today about balancing the shaft. I'm somewhat new to State College, and not familiar with all the shops available here.

 

[BattelWagun]

This is just a suggestion, but while you're at it, I'd go ahead and replace all the seals in the t-case. They're bound to go eventually so you might as well fix 'em while you have it in pieces.

 

[retorq]

Grab the pinion and wiggle it around, see if it has any play before you start tearing into the transfer case. By pulling the drive shaft you eliminated everything in the rear end pretty much ... I had a pinion bearing go out on me, made some noise for a bit and then stopped.

 

[juniorwatson]

Grab the pinion and wiggle it around, see if it has any play before you start tearing into the transfer case. By pulling the drive shaft you eliminated everything in the rear end pretty much ... I had a pinion bearing go out on me, made some noise for a bit and then stopped.

10-4, I'll check that when I get home tonight. I've had a bad pinion bearing in my '96 9C1, and it made noise and no vibration.

 

[BattelWagun]

10-4, I'll check that when I get home tonight. I've had a bad pinion bearing in my '96 9C1, and it made noise and no vibration.

Thats why i said driveshaft, anything bad in the rear end would cause the noise, but no vibration. Not unless it's a warped rear end, which would've still vibrated when you took the driveshaft off. Theres not much on the driveshaft though that can grind so that doesn't totally eliminate the possibilities.

Try swerving around when you're driving and see if the noise stops momentarily, that could mean something else. Let us know about anything else that turns its ugly head up too!

 

[juniorwatson]

Thats why i said driveshaft, anything bad in the rear end would cause the noise, but no vibration. Not unless it's a warped rear end, which would've still vibrated when you took the driveshaft off. Theres not much on the driveshaft though that can grind so that doesn't totally eliminate the possibilities.

Try swerving around when you're driving and see if the noise stops momentarily, that could mean something else. Let us know about anything else that turns its ugly head up too!

I'll give it a shot when I get home tonight. There's absolutely no noise whatsoever, just vibration.

I'll have to take a look at the shaft to DBL check to make sure a weight didn't come loose and fly off.

Unfortunately the closest driveshaft place to get it balanced is a little over an hour away in Harrisburg.

 

[GMC Yukon]

Just my 2 cents.... But I had the rear end yoke go bad on mine were the C clips set inside the metal was worn away.... Replace it and the seal... About a $100.00 from the dealer for parts. And now I roll smooth!

 

[juniorwatson]

Just my 2 cents.... But I had the rear end yoke go bad on mine were the C clips set inside the metal was worn away.... Replace it and the seal... About a $100.00 from the dealer for parts. And now I roll smooth!

The yoke in the rear was in great condition, no wear at all. There was no play that I could feel in the pinion bearing, all felt very tight last night when I pulled the shaft for inspection.

I didn't see any spots where a weight may have flown off, but I did find a shop that is ~30 minutes from work for balancing.

I'm going to take an extended lunch and have it balanced while I wait today.

I'll report back tomorrow morning when I reinstall the shaft.

Thanks for all the suggestions.