99 Suburban Vibration

[InternetMechanic]

Hey, brand new to the forum and thus this is my first thread/post. So go easy on me

I have a 1999 Suburban K1500 5.7L V8 at ~168k miles. I'm currently chasing a vibration/rumble and I'm falling down the rabbit hole.
I noticed a couple weeks ago (drive in to work was normal/good) that on my way home from work there was a pretty bad vibe/rumble from what seems to be the rear end.
Brought it in to a local dealership/shop in the next day or two. They checked it out (I also had noticed and told them to check out a fuel leak by the tank) and told me the rear drive shaft rear u-joint was seized up.
Had them swap out both U-joints on the rear drive shaft and they also replaced the fuel tank, pump, sender, and "repaired" the fuel lines.
The vibe/rumble was "improved" slightly but is still there. I researched a bit and I also noticed one of the rear wheels was missing a balance weight.
Brought it to the shop I bought the tires from and have had other work done. Had them balance all 4 wheels (not road force, can't find anywhere near me that does road force/on vehicle balance) and also did a rotate. Vibe/rumble persisted.
I had problems before when I did all the brakes where I had out of balance/round rear brake drums. So I swapped both drums to known balanced/round drums and still had the vibe/rumble (swapped back to new/current drums after).
Brought it back to dealership to have them check out their work (check u-joints and diagnose the vibe/rumble).
They reported, "Passenger rear axle bearing making noise and vibe. Possible damage to axle shaft and/or housing." also said the u-joints/drive shaft was good (from their work). But they do not do drive shaft balancing or straightening.

More info/specifics on the vibe/rumble:
Starts to be noticeable at about 45 mph and increases in intensity with vehicle speed. High frequency vibe/rumble,shake. More noticeable on incline/decline, also when decel or coasting from higher speed (I think mainly because less/no exhaust or engine noise). Drive/ride height is OEM (besides age of parts). Replaced/updated within last couple years: all 4 shocks, sway bar bushings and links in front, both leaf springs in rear (with all new shackles, bolts etc), new brake pads and rotors in front and new shoes and drums in rear. Driver side front CV joint/boot replaced.
Almost positive it's from the rear end, vibe is noticeable mainly through the floor/seat but seems to vibe the whole cabin. Can feel it in the steering wheel but seems to be more so from the "whole cabin" vibe and not something from the front end (I've felt front end steering wheel shake before from bad/warped rotors and bad tires).
Does not seem to be RPM/engine affected, doesn't change when putting it in neutral. Drive shaft doesn't have any visible dents/cuts and looks to have all balance weights.
Drive shaft is 1 piece. I tested myself under the vehicle (vehicle was in park) and the drive shaft has little to no play when moving it (just up/down to transmission from the transmission mount).
Transmission and engine mounts seem fine from brief inspection.

It's tough for me to do much work or check things at home because driveway is fairly steep slope and only flat location is in double wide garage where both parents vehicles are parked. It's possible for me to check things out myself but it's a lot of work with taking up the garage and not having many tools as well as working a full time job on weekdays. Just wanted to bring this up for anyone to mention things I can check on my own. Also wouldn't have a way to "safely" run the vehicle with it in the air, not even very good to have it in neutral.

Some questions:
If the dealership is correct about pass rear axle bearing/shaft, wouldn't the vibe or noise be noticeable or get worse over time and not on the 2nd trip within a day?
If I do replace the axle bearing should I replace the axle shaft as well? Also should I do both sides at once? (Can get an axle kit that includes the axle, bearing, seal, studs, and lugs)
What are some other ideas/suggestions to check or what this could be?

Please let me know or ask for any details I missed or didn't already mention. I appreciate any help on this and thanks in advance.

 

[Caman96]

Balance weight fall off driveshaft?

 

[InternetMechanic]

Balance weight fall off driveshaft?

From what I saw and the dealership all the weights are still on the drive shaft.

 

[Caman96]

So many things to consider here. How are axle u-bolts? Worth checking either way! Failing, they can change pinion angle. Can be tough to chase down.

 

[InternetMechanic]

So many things to consider here. How are axle u-bolts? Worth checking either way! Failing, they can change pinion angle. Can be tough to chase down.

Do you mean the U bolts on the axle that go over the leaf springs? Those are new with the leaf springs as well as the nuts. Visual inspection I didn't see any cracks in the leaf springs and seem to be tight (just by trying to shake/move them). Haven't gotten a socket/wrench on any of those nuts/bolts to test how tight they are though.
I don't think pinion angle would be the issue with how abruptly this vibration showed up (no accident or major pothole/bump to knock anything loose or change the pinion angle or how the rear end is sitting). But I am no expert and could be wrong about that

 

[Caman96]

I did mean that, it’s good they were replaced too, cause many of these trucks have rotted u-bolts. Weak, worn leaf springs can cause a vibration too! Really, I’m just guessing here, that was just an example of many things to check. Free downloadable manuals on this site and might be worth checking out suggested protocol for chasing down driveline vibrations.

 

[InternetMechanic]

I did mean that, it’s good they were replaced too, cause many of these trucks have rotted u-bolts. Weak, worn leaf springs can cause a vibration too! Really, I’m just guessing here, that was just an example of many things to check. Free downloadable manuals on this site and might be worth checking out suggested protocol for chasing down driveline vibrations.

Yeah the old set of leaf springs were sagging down quite a bit (especially after the towing/hauling I've done with it). Gained probably a good couple inches of clearance in the wheel hubs/wells. I'll check out the documentation you're referencing.

I guess I was mainly wondering if the dealership diagnosis of the rear axle bearing/shaft would even be possible with the symptoms of the vibration and how suddenly it started up.
I feel like if that axle bearing was going bad it would have been a slower process of failing (noisy and gradually get worse) not go from nothing noticeable to a bad vibration.

I appreciate your input on this.

 

[Pinger]

More info/specifics on the vibe/rumble:
Starts to be noticeable at about 45 mph and increases in intensity with vehicle speed. High frequency vibe/rumble,shake. More noticeable on incline/decline, also when decel or coasting from higher speed

'Increases in intensity with vehicle speed'. Does the frequency of the sound increase also? I'd expect it to with an out of balance issue.
A failing wheel bearing will sometimes change its sound during braking. Try a light application of the brake with your left foot while maintaining speed. If the noise changes (usually reduces slightly) there's a fair chance it's a wheel bearing on the way out. If so, eventually there will be detectable radial play at the wheel - but can take significantly advanced failure to show. If you can draw a small quantity of oil from the axle, either visual inspection or analysis may reveal metallic particles consistent with wheel bearing failure - or other wear within the diff.

 

[InternetMechanic]

'Increases in intensity with vehicle speed'. Does the frequency of the sound increase also? I'd expect it to with an out of balance issue.
A failing wheel bearing will sometimes change its sound during braking. Try a light application of the brake with your left foot while maintaining speed. If the noise changes (usually reduces slightly) there's a fair chance it's a wheel bearing on the way out. If so, eventually there will be detectable radial play at the wheel - but can take significantly advanced failure to show. If you can draw a small quantity of oil from the axle, either visual inspection or analysis may reveal metallic particles consistent with wheel bearing failure - or other wear within the diff.

Frequency does seem to increase. Of course it gets harder to tell at higher speeds with air, engine, exhaust noise but frequency and intensity of vibration increases as speed increases.
Tested the braking while maintaining speed and the noise and vibration did not noticeably change at all.
I will note that I've had steering wheel play for years and years.
I've noticed it seems to be pulling left more than usual but nothing extreme. I haven't had an alignment done (that centered and kept the steering wheel centered). With play in the steering wheel I assume some or most of the steering components are worn/aged and an alignment won't be accurate or stay for very long anyways.
I'm starting to think more towards drive shaft balancing? Seems to be "harmonic" and is a high enough frequency that it doesn't seem to me that it relates to tire rpm but more the higher rpm of the drive shaft.
Only one place in my city can do drive shaft balancing but they estimated it would be ~$200 to do so. I can get a new drive shaft on rockauto including shipping for ~$290 (wouldn't include any labor cost to replace current drive shaft of course). So I'm not sure what I should do. Spend the extra money and be "guaranteed" the new drive shaft is straight/balanced or try balancing the current one for less but no guarantee they can balance it (if it's not straight). I also don't want to pull the trigger early on the drive shaft without knowing 99% sure it's causing the problems.
I might contact the dealership (that said it was pass rear axle bearing/shaft) and ask what exactly they found to make that diagnosis.

 

[Caman96]

Did you change leaf spring size when you replaced? Checking pinion angle would be an easy thing to check off.

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