99 Suburban Vibration

[OutlawDrifter]

New driveshaft doesn't mean its straight and or balanced correctly.

I'd also be looking into your pinion bearing, that can cause the vibration as well.

 

[InternetMechanic]

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

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No, should be oem size/ride height. aftermarket leaf springs (don't think you can even get GM genuine or if GM even makes the oem leaf springs anymore).
They were as far as I know, same load rating, same amount of leaves, same shackle, bushings, and bolt sizes.
I changed the leaf springs over 2 years ago. So don't think they are related to this recent issue unless something is broken on them that happened recently.
I'll definitely look into the pinion angle (done a lot of research into this vibration and it is on my list).

 

[Pinger]

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.

Going ever so slightly left-field.... I'd get a Jubilee clip and attach it to the shaft suspected of being the cause. Not sure if you've seen this done - it's in pairs when for real and the heavy parts of the clip (the screws) are arranged such as to balance the shaft by trial and error. However, if you try one and are very very luck (not going to happen!) you rebalance the shaft. More likely you make it worse but it is still the same vibration. Or, you introduce another vibration which suggests the problematic one isn't with the shaft. If you try this, be prepared to move the Jubilee clip around length wise ie, each end and mid position (any imbalance on the shaft could be anywhere along its length).
Not a solution (though possibly could be), more a diagnostic effort.

 

[InternetMechanic]

Going ever so slightly left-field.... I'd get a Jubilee clip and attach it to the shaft suspected of being the cause. Not sure if you've seen this done - it's in pairs when for real and the heavy parts of the clip (the screws) are arranged such as to balance the shaft by trial and error. However, if you try one and are very very luck (not going to happen!) you rebalance the shaft. More likely you make it worse but it is still the same vibration. Or, you introduce another vibration which suggests the problematic one isn't with the shaft. If you try this, be prepared to move the Jubilee clip around length wise ie, each end and mid position (any imbalance on the shaft could be anywhere along its length).
Not a solution (though possibly could be), more a diagnostic effort.

I have watched some videos on similar diagnostics I think. Using hose clamps or similar to add weights. I'll definitely have to try this out when I have time (probably this weekend).
Although, would there be enough weights added to change the vibration enough to notice it while driving? I ask because in the videos I watched they were running the vehicle in the air and monitoring the vibration directly from under the vehicle. Just worried I try adding some weights to the drive shaft and test drive it afterwards and not notice any differences...
Thanks for the idea!

 

[Caman96]

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 personally would resolve all of this, before balancing the driveshaft. There might not be any vibration after it’s all back in spec.

 

[Pinger]

I have watched some videos on similar diagnostics I think. Using hose clamps or similar to add weights. I'll definitely have to try this out when I have time (probably this weekend).

That's the kind I have in mind - here, in the UK we refer to them as Jubilee (a brand name).

Although, would there be enough weights added to change the vibration enough to notice it while driving? I ask because in the videos I watched they were running the vehicle in the air and monitoring the vibration directly from under the vehicle. Just worried I try adding some weights to the drive shaft and test drive it afterwards and not notice any differences...
Thanks for the idea!

I guess you could use a few all aligned with each other to accentuate the effect - but not so much as to mask the original vibration if it is from another source. You seem to have a firm comprehension of your vibration - which leads me to thinking you are perceptive to any change - which is what is required here.
It will possibly cost you in time - but the hardware is cheap!

 

[Erik the Awful]

When I took a transmission/drivetrain class twenty-five years ago, we were taught to use hose clamps and vibrating reed frequency meters to resolve driveshaft vibration. You can't even find a vibrating reed meter any more.

 

[InternetMechanic]

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 the suggestion!
Now I know it was the drive shaft out of balance for sure and can move on from this vibration.
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)

 

[Caman96]

Balance weight fall off driveshaft?

Post #2 Lol

 

[InternetMechanic]

Post #2 Lol

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!