Noise in driveline, pinion bearing?

[dkad260]

Thanks again for the measurements @swathdiver, the 1.75" seating depth translates to 44.45 MM so this is close enough. My goal was no less than 1.75" but really can't go too much farther, almost centered in the boss. Maybe it can be bottomed out, but GM likely did this for a reason.






Ready to go, new parking shoes also done, just need fluid and a test drive today.




Why MM you may ask...I always measure imperial but it's easier for me to visualize 1MM increments over feeler gauge increments...lol.

 

[dkad260]

Late update, all is back together and I have driven it for a few days. The light droning sound that seemed to follow the exhaust note is gone, much, much quieter ride under load, almost no noise.

However, the faint noise is still there, and I went back to see if the pinion yoke had any movement with a prybar but found some slop in the transfer case output shaft.

I assume this is a bushing? What is the acceptable amount of movement?

Can I split the case and replace the bushing, or do I need to replace the whole case half?

 

[Geotrash]

Late update, all is back together and I have driven it for a few days. The light droning sound that seemed to follow the exhaust note is gone, much, much quieter ride under load, almost no noise.

However, the faint noise is still there, and I went back to see if the pinion yoke had any movement with a prybar but found some slop in the transfer case output shaft.

I assume this is a bushing? What is the acceptable amount of movement?

Can I split the case and replace the bushing, or do I need to replace the whole case half?

I believe it’s a bearing. Mine is very similar on my 2007, and I haven’t worried about it for 40,000 miles now. Lol.

 

[dkad260]

I believe it’s a bearing. Mine is very similar on my 2007, and I haven’t worried about it for 40,000 miles now. Lol.

Ha, copy that.

Well, I spoke to a company who remanufactures the transfer cases and they said a little movement is ok...so I need to see exactly how much movement there is.

Yesterday and today, I wanted to at least try a different fluid in the diffe. Currently I'm using Amsoil 75-90 front and rear, and just for the sake of science, I went with Valvoline synthetic, 2 quarts of 85-140 and 3/4 qt of 75-90. For the front, one quart of 85-140 and 1/2 at of 75-90. I wanted to thin it out a little.

Having .010" backlash at least on the rear, I felt ok with this thicker concoction.

Upon changing the front, I came across the LF axle shaft had a decent amount of play at the diff.

I put about 3 miles of highway and it does seem slightly quieter, but could be placebo, but it seems quieter.

I can still hear the faint noise though and it's hard to say how much the sound can travel under the vehicle. I want to speculate there should be very little movement on the front axle, this seems like alot.

I strained and saved the old fluid from the front diff, not much came out, hard to decipher with the bubbles but not too much metal flake, but still a little concerning.

 

[Geotrash]

Ha, copy that.

Well, I spoke to a company who remanufactures the transfer cases and they said a little movement is ok...so I need to see exactly how much movement there is.

Yesterday and today, I wanted to at least try a different fluid in the diffe. Currently I'm using Amsoil 75-90 front and rear, and just for the sake of science, I went with Valvoline synthetic, 2 quarts of 85-140 and 3/4 qt of 75-90. For the front, one quart of 85-140 and 1/2 at of 75-90. I wanted to thin it out a little.

Having .010" backlash at least on the rear, I felt ok with this thicker concoction.

Upon changing the front, I came across the LF axle shaft had a decent amount of play at the diff.

I put about 3 miles of highway and it does seem slightly quieter, but could be placebo, but it seems quieter.

I can still hear the faint noise though and it's hard to say how much the sound can travel under the vehicle. I want to speculate there should be very little movement on the front axle, this seems like alot.

I strained and saved the old fluid from the front diff, not much came out, hard to decipher with the bubbles but not too much metal flake, but still a little concerning.

View attachment 405181

If it ain't leakin', it's good. I've replaced the pax front axle seal on my '07 because it was leaking but the bearing seemed fine. I also have similar play on the drivers side though.

 

[dkad260]

Late update, but I was able to get some chassis ears on the front diff, TC, and rear diff. Both the front and TC seem quiet, however the rear pinion sounds like something is going on.

This is under load, coast, and decel. Oddly enough, it seems rather quiet in the cabin, turn the radio up and you might not hear it.

I think I'm just going to finish refreshing this rear axle, already did axle bearings and axles, this week hopefully the remaining bearings along with OE ring and pinion gearset.

 

[j91z28d1]

how did you record that?

seems very high pitch for a pinion bearing. but I've never had a mic on one while driving. so maybe?

 

[dkad260]

how did you record that?

I used Chassis Ears, clamping the mic to the front of the rear diff, and ran the output through the aux input of the Yukon's radio, recording the audio as a video clip through my cell phone.

For comparison, this is the front diff I recorded at the same time. The clicking was some light interference.

 

[dkad260]

I almost have the diff torn down, just need to remove the pinion races but so far I have .011" backlash and some wear on the pinion race.

 

[Geotrash]

I almost have the diff torn down, just need to remove the pinion races but so far I have .011" backlash and some wear on the pinion race.

View attachment 405814

I’d say that’s accurate!