99 Suburban Vibration

[Caman96]

I'm not 100% sure if there was a weight there. It doesn't immediately appear like a spot where a weight was at first glance. If so I guess you were very much correct!

Just teasing, Pinger always brings a lot to the table! Glad you found it too.

 

[Pinger]

UPDATE:
Tried the hose clamps on the driveshaft. 1st test seemed to make it worse. So I flipped it by 180 and added another hose clamp (because 1 didn't make a big difference).
I noticed that the 180 spot I was tightening them down there was the sticker/label was for the drive shaft but it has some rectangular outlines of rust. Not sure if there was a weight there before and it fell off or what.
Put the 2 hose clamps weights tightened down right where that rectangle was and test drove again...
THE VIBRATION IS GONE! (almost entirely, would need to fine tune the weights for balancing to get it perfect).
I can't believe how lucky I got with the placements and how little time it took me. Thanks again to Pinger for his suggestion!
Now I know it was the drive shaft out of balance for sure and can move on from this vibration.

Result! For me that is - someone actually listened to what I said - that's a rarity!
Really pleased that it worked as a diagnostic...

Cheap fix of $4 in hose clamps and some test drives to find and "fix" this problem/vibration. I wonder if I should stick with the hose clamp balancing or if I should get it "professionally" balanced? (~$200)

...and possibly a solution too. Given that hose clamps are (or were) an accepted way of balancing a shaft, if you are happy that it's spot on (or can further fettle the positioning a touch more to improve if that's possible) then I don't see the need for professional balancing. Others who know these trucks better may have a different view though.

 

[Erik the Awful]

If you have a welder you can tack a washer on there. Every driveshaft I've ever had professionally balanced came back with a washer welded on it.

 

[Scooterwrench]

Just leave the hose clamp and check periodically to make sure it is still tight.

 

[InternetMechanic]

I tried adjusting the hose clamps and didn't improve it any. Only made it worse or come back by moving them. Added a 3rd hose clamp and that made it worse too. I'm wondering if I got EXTREMELY lucky and placed them almost perfectly on my 2nd try?
I also confirmed by a closer inspection that it was not a weight that was there but just the label/sticker (the rust outlines I was talking about).
I now only get a vibration (more of a shake or rumble) at higher speeds (~80mph+) but does not seem to be the same vibration as before, more so something else that is causing it. This one makes an actual noise and I'm thinking it might be the axle/wheel bearing that the dealership shop was mentioning. I don't think I need to chase down this "problem" though as I would rarely if ever be going that fast. Unless it continues to worsen and be noticeable and lower speeds.

I noticed while under the vehicle that a hose coming from the top front pass side of the rear diff that goes up and seems to go to a bleed/release valve about half way the hose is almost completely torn. It is "open" essentially. Which can NOT be a good thing. Does anyone know if this is a pressure release/overflow for the rear diff fluid/oil or is it for the axles or the housing? If its for the rear diff I should probably get the rear diff oil/fluid checked and probably replaced? And of course that hose fixed or sealed back up.
Just thinking that if dirt/debris was getting in there and its for the axles that it could be getting in there and destroying the bearings? Or if it goes to the rear diff its destroying everything.
Not sure if I should make a new thread about this and/or for the 80mph+ vibration but just thought I'd add on to this thread for now.

 

[Caman96]

I noticed while under the vehicle that a hose coming from the top front pass side of the rear diff that goes up and seems to go to a bleed/release valve about half way the hose is almost completely torn.

Yes repair this, it is your axle vent.

 

[InternetMechanic]

Yes repair this, it is your axle vent.

Of course I don't know how long its been this way but I assume with it allowing "stuff" to get in there it probably has made the rear axle bearings shot?
Would that also allow stuff to get into the rear diff or no? I guess to replace the axle bearings the rear diff has to get opened up anyways but...

 

[Caman96]

It wouldn’t hurt to open it up, inspect everything and refill with new oil. Definitely repair the vent hose too.