Mysterious truck noise, part 2

[Vbb199]

As a preface, forgive me people if my spelling is ******, im having difficulty seeing right now. I think i need reading glasses.


so i had that annoying axle whine return a little after i installed my posi a couple weeks ago. Very shortly actually.
Today i pulled apart the axle again, since i probably need ti change the fluid from any grease or initial clutch dust from the yukon.

Inspected my carrier and pinion bearings. All good. Nice healthly wear patttern in bearings. No bad parts, but i warrantied them anyways thru parts store. national brand.

Gears looked ok too. Installed new pinion bearings anyways.
I previously torqued them until i got 19 in/lbs of preload. The appropriate preload range is 14-19 in/lbs.
Today, i torqued with with new crush sleeve to like, 14 in/lbs thinking maybe the bearings i had just couldnt take that much tension (19 ib/lbs)

Still whines when i decelerate.

I know everyone may not have worlds of knowledge on this, and neither do i, but im open to suggestions, maybe im overlooking something.


Heres the facts:
When i setup those rear gears 3 or so months ago, i rode on them for like 1.5-2 months. Not a whine, squeak, or whirl. That was with new carrier bearings, and new pinion bearings, and new gears. All was right in the world, until the truck fell off of the lift, and ive been chasing this noise since then. Im really ******* scratching my head on this one. And need a suggestion.

Im out of ideas. No matter what ive done, the whine WILL NOT go away. I had a thought today just a moment ago, which prompted me to message. What if when it fell down, it bent an axle shaft, and that bent axle shaft(s) has wiped out the wheel bearings ?

Some clues hat makes me think bearings:

On a cold startup, heading down the road, i wont hear a noise anywhere until about 10-15 min into driving, and the sound jusy increasingly gets worse and worse. Its like a thermal issue. Something heats up then begins its BS

the facts
• Its not a continuous whine, at any speed, taking off or slowing down, or cruising, like a bad gear setup.

• It doesnt whine when accelerating, like carrier bearings.

• It only whines when i decelerate, and very occasionally at cruising speeds for a moment, then goes away.

The sound description:


Occasionally cruising i will hear a random "eeeeeeeeeeeeeeeeeee" that sounds like its resonating thru a tunnel, but goes away shortly after.

When slowing down, coming to a stop it makes a "woo woo woo woo woo wooooo" sound (lol)

technical details of my current axle setup to eleminate any sort of confusion

new crush sleeve as of today, torqued at 300 ft lbs,
Pinion preload, as i said, 14 in/lbs
Carrier bearings 2 weeks old, caps tightened to 60 ft/lbs
Backlash was set at 7 today.
Pinion bearings and races replaced again, today, despite me having no reason to suspect them being bad, all were greases prior to install.
Yukon posi in axle, noise was present prior to install. Additive added. 80w-90 gear lube.

Richmond gears in axle. 4.10 r/p
I did do proper annealing cycle, per spec. (300 miles, stop, cool down, 300 miles, stop, cool down, etc etc. )

Again, i had no issue whatsoever when i did gear install 3 months ago. No whine, no noise, nothing, until truck fell off of lift, and tires contacted concrete truck during fall, with truck in park.





Hit me with WHATEVER you got im all ears.

I may be an idiot, but given my resume of ability, and background in this and other things, i find it highly unlikely it was my job with the gears.

I personally think it is something else.
Read over all the details, and lemme know what you gents think.

 

[legopnuematic]

Maybe get the wheels off the ground and pop it in neutral and have someone turn wheel and use a stethoscope and listen around each bearing and see if you can hear a discrepancy?

Could something with the brakes gotten jolted during the fall?

 

[Vbb199]

Maybe get the wheels off the ground and pop it in neutral and have someone turn wheel and use a stethoscope and listen around each bearing and see if you can hear a discrepancy?

Could something with the brakes gotten jolted during the fall?

Its a good thought for sure. All of this.
The inner pinion race from the richmond gear set showed evidence that fall was hard enough , it deeply set the pinion towards the input yoke, and wore a nice ring in it.
So anything is really possible.

You must be registered for see images attach

 

[Vbb199]

Its like, without tooting my own horn, i have enough knowledge to be dangerous. And it ****** kicks my ass so much sometimes.
I will hear a tick in a motor, and instead investigating maybe it was just low on oil and a lifter was upset and ticking, i take the motor apart and completely tear it down for inspect, and finally rebuild it, When the issue was just a simple ******* oil level issue.

Im absolutely terrible about it. To the worst degree.

And again, im not tooting my own horn here, because there is gents here with decades of experience on me that have seen it all.

I am just explaing how my brain works, so i need outside opinions.

 

[Turbo4whl]

Please post the pictures of the gear pattern that you had in the post when you set the gear adjustment.

 

[Vbb199]

Please post the pictures of the gear pattern that you had in the post when you set the gear adjustment.

This is when i set them up 3 months ago with like, 16 in/lbs of pinion preload, maybe .008" lash.

I checked mesh today, same deal, didnt take pics

also had a similar mesh when i installed posi

You must be registered for see images attach

You must be registered for see images attach

 

[Grit dog]

You’re far more knowledgeable about axles than I, but given the shock loading falling off the lift and you mention possible bent axle shaft, have you actually checked the axle shafts or the axle tubes are straight?
Idk how you’d check the axle tubes except visually, but it’s a suggestion.

 

[Vbb199]

You’re far more knowledgeable about axles than I, but given the shock loading falling off the lift and you mention possible bent axle shaft, have you actually checked the axle shafts or the axle tubes are straight?
Idk how you’d check the axle tubes except visually, but it’s a suggestion.

idk either to be honest, i guess with the big precision ground straight edge we have at the shop, idk how else to check it. lol
im beginning to wonder if thats my issue.... i noticed today, for the first time, since i snapped out of the little place my brain was trapped in, riding slow in the truck, it felt like the truck was riding on tractor tires (over exaggerated) in the rear axle. im kinda wondering now... was that my brain trying to just settle this? or was that real? hard to tell. she sits on AT tires. lol

i think imma jack it up tomorrow and put it in gear and let the tires spin, see if maybe something is janky. im out of ideas... which is why im asking for help from you guys out there in GMSB land

 

[Turbo4whl]

Okay, top picture is the drive side, coast side does not matter. The pattern should be low on the gear (towards the center) When the gears are under load the gear contact moves up. In this case, it will under load move up and off the tooth.

Next, the pattern needs to be centered on the tooth, it is not. The pinion gear needs to be moved in to the gear more. On new gears the pattern should not be off the inside edge.

Re-shim the pinion closer to the ring gear. Reset the backlash and check the result.

When everything is right, the pattern should be centered and low on the gear.

When checking the result the gear set needs to be loaded. The way I do it is to take a pry bar, slide it between the housing and the ring gear, away from the teeth. Then I spin the pinion with a socket an ratchet. Sometimes hard to do by yourself. Need to keep constant drag on the gear while turning the pinion.

 

[Vbb199]

Okay, top picture is the drive side, coast side does not matter. The pattern should be low on the gear (towards the center) When the gears are under load the gear contact moves up. In this case, it will under load move up and off the tooth.

Next, the pattern needs to be centered on the tooth, it is not. The pinion gear needs to be moved in to the gear more. On new gears the pattern should not be off the inside edge.

Re-shim the pinion closer to the ring gear. Reset the backlash and check the result.

When everything is right, the pattern should be centered and low on the gear.

When checking the result the gear set needs to be loaded. The way I do it is to take a pry bar, slide it between the housing and the ring gear, away from the teeth. Then I spin the pinion with a socket an ratchet. Sometimes hard to do by yourself. Need to keep constant drag on the gear while turning the pinion.

im all for this, would take a couple hours worth of work, i understood contact should be right in the middle, and it looks like it is? am i completely flaking out?
you think this is causing the noise? as i said, there was no issue with this pictured setup until the fall occurred

im completely willing to entertain anything someone suggests at this point but even if the contact is a bit shallow, it didnt cause any issues until "that day"

 

[Turbo4whl]

So pull the axles out and look close at the drive ends. If the housing is bent, the axles will have new wear on the ends since they are not lined up any more. Also check the side gears for uneven wear.

 

[Bextreme04]

While you are at it, I’d take a look at the brake hardware in the drum... a hard enough hit to smash the pinion like that might have knocked something loose in there.

 

[Vbb199]

So pull the axles out and look close at the drive ends. If the housing is bent, the axles will have new wear on the ends since they are not lined up any more. Also check the side gears for uneven wear.

While you are at it, I’d take a look at the brake hardware in the drum... a hard enough hit to smash the pinion like that might have knocked something loose in there.

Alright... i guess i will check it out this weekend, as you know this will require opening the cover.



Anyone else have suggestions to toss at me?

 

[Vbb199]

Had a call with the wifes grandfather.
Hes i believe a late 60 year old man, whose been a diesel and regular mechanic all his life, and i dont mean auto zone mechanic.


I gave him the entire story of the truck.

He thinks ive either
A. Got a bent axle shaft that wiped out wheel bearing
B. The axle gears got damaged from the fall, which that slight damage turned into collateral damage on the whole gear set.


Thoughts?

 

[gotyourgoat]

They sound like reasonable answers to the problem, as unfortunate as that may sound.