Deep warbling noise on upshift light throttle

[Matahoe]

I am starting to notice this noise under the drivers floor area. It happens only when upshifting into OD with very light throttle. Its a deep grumbling, warbling resonant sound. I researched it a bit and some think it could be the CV shaft or center carrier bearing. I don't think I have a center bearing since I my Tahoe isn't as long as a Yukon XL. let me know what you think.

 

[rockola1971]

No center carrier bearing. Check your tranny fluid. Does it smell burnt, is it getting more brown than pink? During a shift from 3-4 your 2-4 band comes into play and could be worn and slipping.

 

[Matahoe]

I noticed the sound also happens when I put it manually into 3rd gear as well. I think that pretty much rules out torque converter and transmission.

It sounds like some type of bearing running dry. I am going to take a look and check the driveshaft. The noise does not increase in pitch as the vehicle moves through the gears so the noise is definitely related to driveshaft speed. I did notice some wetness around the front left CV axle where it goes into the front axle seal. Wetness could be residual from a previous fix? Maybe the bearing is shot there? I just changed the front diff fluid twice in as many years. Didn't notice any metallic flakes.

 

[rockola1971]

Could very well be a front diff support bearing. THat would be my second guess and what id look at next.

 

[Matahoe]

Not sure which bearing in this diagram.


(1) Front Drive Axle Inner Shaft
(2) Front Drive Axle Inner Shaft Seal
(3) Front Drive Axle Inner Shaft Bearing
(4) Front Drive Axle Inner Shaft Housing
(5) Front Drive Axle Inner Shaft Retaining Ring
(6) Front Drive Axle Inner Shaft Bolt
(7) Front Differential Carrier Case Bolt
(8) Front Differential Carrier Case Half
(9) Front Differential Carrier Half Lock Pin
(10) Front Differential Bearing Adjuster Lock Pin
(11) Front Differential Case Half Lock Pin
(12) Front Drive Axle Clutch Shaft Bearing
(13) Front Differential Bearing Adjuster Nut
(14) Front Differential Bearing Adjuster Nut Sleeve
(15) Front Differential Case Side Bearing Cup
(16) Front Differential Case Side Bearing
(17) Front Differential Ring Gear Bolt
(18) Differential Pinion Gear Thrust Washer
(19) Differential Pinion Gear
(20) Differential Side Gear Thrust Washer
(21) Differential Side Gear
(22) Differential Pinion Gear
(23) Differential Pinion Gear Thrust Washer
(24) Front Differential Side Gear
(25) Differential Side Gear Retainer
(26) Front Differential Side Gear Thrust Washer
(27) Front Differential Pinion Gear Shaft
(28) Front Differential Case
(29) Differential Pinion Gear Shaft Lock Bolt
(30) Differential Case Side Bearing
(31) Differential Case Side Bearing Cup
(32) Front Differential Ring Gear
(33) Front Differential Bearing Adjuster Nut
(34) Front Differential Bearing Adjuster Nut Sleeve
(35) Front Differential Bearing Adjuster Nut Lock
(36) Front Differential Carrier Bushing
(37) Front Differential Carrier Case Half
(38) Front Differential Drive Pinion Gear Outer Bearing
(39) Front Differential Drive Pinion Gear Outer Bearing Cup
(40) Front Differential Drive Pinion Gear Oil Seal
(41) Front Differential Drive Pinion Gear Deflector
(42) Front Differential Drive Pinion Gear Yoke
(43) Front Differential Drive Pinion Gear Yoke Washer
(44) Front Differential Drive Pinion Gear Yoke Nut
(45) Front Differential Carrier Bushing
(46) Front Differential Inner Shaft Bearing
(47) Front Drive Axle Inner Shaft
(48) Front Drive Axle Inner Shaft
(49) Front Axle Vent Hose
(50) Front Axle Vent
(51) Clamp
(52) Front Differential Carrier Vent Hose Connector
(53) Front Differential Carrier Oil Drain Plug
(54) Front Differential Carrier Oil Drain Plug Washer
(55) Front Differential Carrier Oil Fill Plug
(56) Front Differential Carrier Oil Fill Plug Washer
(57) Front Differential Drive Pinion Gear Bearing Spacer
(58) Front Differential Drive Pinion Gear Inner Bearing Cup
(59) Front Differential Drive Pinion Gear Inner Bearing
(60) Front Differential Drive Pinion Gear Inner Bearing Shim
(61) Front Differential Drive Pinion Gear

 

[rockola1971]

#3 if the "wetness" youve seen is coming from #2 area.