Counting the threads or "feeling" the slack is not the way to correctly set or verify pinion preload. Nor is marking the nut which some do. Only real way is to correctly prep and measure it with an inch/pound torque wrench.
Need help diagnosing drivetrain noise on 2012 Yukon
- Thread starter i6pwr
- Start date
What I’ve eluded to is a starting reference point…. Most shops won’t remove a differential carrier just for a pinion seal replacement. Inch pound preload specs are for fresh bearings and crush sleeve. I have had seasoned techs do this as I’ve mentioned and some that could do this by feel also. As has been mentioned in this thread, it is an “art” that is practiced.
Update on this, I pulled the rotor and the seal is definitely leaking.
Upon pulling the axles, there is very noticeable wear on the axle. this is the RH, the LH axle looked ok but still had some movement.
I have about .030" of total movement at the axle flange, maybe a bit more. Luckily the fine metal shavings seem to be contained to the area around the bearing/seal, and ABS tone ring. Nothing inside the RH axle tube,/pumpkin, or LH tube. LH axle had some movement also but about .010".
I'm replacing both axles/bearings and will go from there.
The mesh pattern looks ok, slight bias to the heel, not sure if that was factory or from the pinion seal replacement, backlash is .010.
That amount of pitting will surely make some noise, least this is a start for sure.
Wow. I would never have expected that. Thank you for posting the pics.
Still have that faint higher pitched howl under load, seems more prevalent when warmed up, but completely goes away when you lift off the gas.
This has been the main noise I have been hunting down, the axle shaft bearings have solved the accompanying groan.
I will get some chassis ears hooked up this week and hopefully see where it's coming from.
This "howl" isn't at low speed, doesn't change pitch with a higher load, and is quiet in coast.
The audio clip I posted is still accurate.
This has been the main noise I have been hunting down, the axle shaft bearings have solved the accompanying groan.
I will get some chassis ears hooked up this week and hopefully see where it's coming from.
This "howl" isn't at low speed, doesn't change pitch with a higher load, and is quiet in coast.
The audio clip I posted is still accurate.
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I was going to suggest getting some chassis ears to try and isolate the noise. I have set that hooks up to my scope.
I was able to do this today, audio was through the Yukon's stereo, recorded on the cell phone..
I've never heard a pinion under load at highway speed, so I have nothing to compare it to. However I did listen to the front and it was nearly quiet.
Anyway, here's the rear pinion at around 50 MPH, acceleration, deceleration, and coast...sounds pretty bad IMO.
If you had the radio turned up at a normal listening level you probably wouldn't hear anything inside the vehicle.
Sounds like you might have a pinion bearing race with some spalling damage.
That does sound bad.
I have the rear out of the vehicle and tearing it down today.
I have .011" backlash,.along with this front pinion race.
Total roating torque of pinion and carrier is 4 inch pounds. Breakaway was 4 inch pounds also.
Inner pinion race wasn't as bad.
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Front race is a bit rough, though I’ve seen worse. What do the rollers look like on that bearing?
Sorry for the late reply,
This is the outer pinion bearing.
I finished the rear Friday and went on a test drive.....nice and quiet now.
I ended up with a .010" thinner shim on the pinion and .006" backlash.
Pattern location is more even on both drive and coast, slightly biased to the toe which should work. Was my first diff rebuild, seemed to turn out good,.was definitely a nervous first few miles though.
Drive
I think the front diff is next. I put chassis ears on the LH and RH output and the pinion. I can move the LH shaft up and down a little bit and the pinion bearing has noise similar to the rear but not as bad.
The front is definitely easier to R&R and I might just change out the bearings only if the gears look good.
I'm no pro, but I've done quite a few without a failure. Granted I bought all the right tools for setting backlash and preload. I say you did an excellent job. I would not hesitate to run your pattern. I'm glad to hear you got it sorted out.
I bought a spare front diff from one of the local salvage yards. I'm still having some issues with the differential outer bearing races spinning in the housing, even with proper setup, preload at 55 foot pounds, and sleeve retaining compound. The spinning of the races eventually seems to cause the aluminum lock ring to strip, and it loosens the preload. I had one fail halfway into the return trip from Tucson, AZ to San Diego, CA. I had to pull over and add fluid every 40 miles to keep it from running dry. That trip sucked. I might use the mig welder to tack the adjusters on the next one I rebuild.
I bought a spare front diff from one of the local salvage yards. I'm still having some issues with the differential outer bearing races spinning in the housing, even with proper setup, preload at 55 foot pounds, and sleeve retaining compound. The spinning of the races eventually seems to cause the aluminum lock ring to strip, and it loosens the preload. I had one fail halfway into the return trip from Tucson, AZ to San Diego, CA. I had to pull over and add fluid every 40 miles to keep it from running dry. That trip sucked. I might use the mig welder to tack the adjusters on the next one I rebuild.
Are you sure it's not the thin flat roller bearing that sits next to the spanner? That could be mistaken for a bearing race if we are speaking of the same item.
Unfortunately I'm 100% sure it's the outer differential carrier bearing race in the left side housing that spins and causes the preload adjuster to fail. It was the failure mode on the original diff, as well as the spare one I got at the yard. If I get to tear into the unit sitting in the garage soon, I'll post pics with explanation.
For roughly $7 if you have a welder you can make your own preload setting socket. 27mm socket from Harbor Freight and a piece of 3/16" key stock cut into 1 1/2" long pieces welded 120 degrees out gets it done.
Ouch, copy that.
I'll definitely take a close look at mine when I open it up. Looking forward to.your teardown. Nice tip on the socket.
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