G80 Rear Diff Clicks and Chirps

[kyle411]

I have noticed a somewhat random clicking sound coming from the rear end of my 00 Sierra SLE 4X. If I really stomp on it from a dead stop, I get a few creaking-sounding clicks, and sometimes even a bird-like chirping that increases with increasing speed--this sounds absolutely horrible. I also get random clicking noises while just driving around town--they really sound like the frame creaking, but its definitely coming from the rear-end (my wife drove my goofy butt around whilst I hung off the tailgate).

 

SO, this morning I drained the diff and pulled the cover to take a peek. Ring, pinion, spider gears---all visible parts showed no sign of wear. Didn't jack up rear, and locking side of the cage was on the opposite side. Old gear oil had nothing but tiny flecks of metal, magnet on cover had very few tiny shavings, and residual oil in bottom if pumpkin had nothing but tiny flecks of metal... No signs of failure or abnormal wear.

 

I've heard that these locking rear ends start to make clicks and chirps when they start to go bad. Plan to take this in ASAP, but would appreciate any input from you folks...

 

Thanks

[snoman]

The gov lock in a a 8.5 inch axle is not noted for it durabilty or longivity. YOu might try a fresh fluid change with some limited slip additive. If the noises are coming from there it is likely from the clutch pack in it.

[GMCTech]

Did you drop the driveshaft and check the u-joints?

 

A dry joint may not be noticed without removing the driveshaft and articulating the joints by hand.

 

Seen a ton of u-joints make thiis exact same noise.

 

Hope this helps.

[snoman]

Did you drop the driveshaft and check the u-joints?

 

A dry joint may not be noticed without removing the driveshaft and articulating the joints by hand.

 

Seen a ton of u-joints make thiis exact same noise.

 

Hope this helps.

Yes a good possibility. Sometimes I have found that you can insert a finger in between the u joint yokes and rock/twist drive shaft back a forth (engine of in neutral with park brake on) and feel for slop or wear in joints. If you can feel it, it is worn for sure and needs servicing.

[kyle411]

nope, didn't drop the drive shaft, but appreciate the input. I wrenched a bit on the shaft with the rear end jacked up and could not discern any play in the U-joints, but realize that the method I used wasn't the best...

 

SNOMAN--after taking a look at everything I refilled with new Mobil-1 synthetic 75W-90 and then took it out to put it through its paces... Diagnosis=same ol stuff... I thought the 99 and newer rigs didn't need the additive, especially if you go with synthetic gear oil.

 

I guess I forgot to mention in my first post that I had inspected the diff, replaced the gear oil, and then took the truck out to see if it made the same noises (it did).

 

I'm betting on something just starting to go south in the differential, but it would be pleasant if its just a u-joint.

 

Thanks, Gentlemen.

[chuckp]

U-Joints........................

[snoman]

nope, didn't drop the drive shaft, but appreciate the input. I wrenched a bit on the shaft with the rear end jacked up and could not discern any play in the U-joints, but realize that the method I used wasn't the best...

 

SNOMAN--after taking a look at everything I refilled with new Mobil-1 synthetic 75W-90 and then took it out to put it through its paces... Diagnosis=same ol stuff... I thought the 99 and newer rigs didn't need the additive, especially if you go with synthetic gear oil.

 

I guess I forgot to mention in my first post that I had inspected the diff, replaced the gear oil, and then took the truck out to see if it made the same noises (it did).

 

I'm betting on something just starting to go south in the differential, but it would be pleasant if its just a u-joint.

 

Thanks, Gentlemen.

I know that a additive is not required but when plates are warn it can help. Does squeak change with throttle presuure and change with striaght or turns?

[kyle411]

Snoman--10-4 on the additive. I was confused as to whether or not it was "required'...

 

The only way I can reliably get the noise to occur is when I firewall it from a dead stop, and even then it only happens about 1/3 of the time. Otherwise, I get random clicks while driving around town, whether going straight or around a turn or...

 

When I get the darn noise to occur, it starts with a few random clicks that don't seem to match revolutions or engine speed, then breaks into a bird-like chirping that matches revolutions and speed until I let off the pedal. I can only get it to chirp with a jackrabbit start, have never heard the chirp whilst driving around town.

 

On a separate note, as I noted above I can now only get the thing to make nasty noises about 1/3 of the time when I firewall it from a dead stop now that I have changed out the gear oil. B4 I changed the fluids, I could get it to go about 9/10 of the time... So the diff fluid change helped, but didn't cure the noise.

 

I'll definitely ask the mechanic to drop the drive shaft and check out the u-joints B4 tearing into the differential. Would be very sweet if that is all that is wrong.

[RyanbabZ71]

Does it sound like a gernade going off Mine has done this since new if the locker kicks in (especially on wet pavment/grass). It really scares passengers or cars behind me but I must say it kicks in and works fine seems like the noise is the locker engaging. I have near 48K miles on mine and it has worked great. Its not the U-Joints (just changed em and it still makes the noise).

[snoman]

That gov loc in a 8.5 is a grenade waiting to go off! If you ever replace one, do not rebuild it, replace it with a different type completely.

[kyle411]

That gov loc in a 8.5 is a grenade waiting to go off! If you ever replace one, do not rebuild it, replace it with a different type completely.

 

Snoman--You were talking to RyanbabZ71, right???

[kyle411]

Problem Solved...

 

Front u-joint was trashed.

 

Thanks to those of you who took the time to read my posts.