Driveline screech/squeal

[VetteRacer]

Hello, everyone. I've been lurking in the shadows for a while, but my truck has prompted me to join in.

I have a 2002 Chevy Duramax 2500HD with a 6-speed and just over 18,000 miles. This past Friday I noticed a metalic squeal (like a bearing going bad) that I originally thought was a brake squeal. On further investigation, I found that (with the truck jacked up) I could rotate the driveshaft by hand and hear the sound coming from the rear of the transfer case.

When driving the truck, the sound is most noticeable at low speeds (35-45 mph), seems louder when starting to brake, and is not affected by popping either the transfer case or the transmission into neutral. Engaging four-wheel drive doesn't change it either. The transfer case and transmission oil levels are full.

Any ideas? I searched on here and found a couple of messages (one from BradL in December 01 and one from Cowboy_120 in March 02) that described what may be the same problem, but I didn't see any solutions posted. I plan to take the truck into the dealer tomorrow, but I want some ammunition for the inevitable "discussions".

Any information would be appreciated. Thanks.

[NutNbutGMC]

^....One-piece or two-piece shaft?

[VetteRacer]

I have a two-piece driveshaft. I have not experienced any driveline shutter, although I have noticed an occasional bind when I press in the clutch when the driveline is under load. I've found that a smooth transition from the accelerator to the clutch will eliminate the bind.

The noise did appear to be coming from forward of the driveshaft, but I suppose it could have been transmitted from the carrier bearing.

[NutNbutGMC]

^...I really had no point in asking, other than curiosity and a comment. There is obviously a problem (or the potential for a problem) with the 2-piece component. Personally, I'd have it replaced under the guidelines of the revised TSB. If it IS the problem, or related to it, there is one less troubleshoot you have to consider. The one-piece replacement is easy enough, as long as you know what is going on, thus no potential BS from a Service Rep. Get the TSB number (readily available) and go forward with the complaint of "launch shudder" under a load. Plan on two trips (min) to the service area. And I'll say this in advance, one more time.... DO NOT allow them to cut the X-member. One last time... DO NOT allow them to cut the cross-member.

Just my $0.02 worth.

[cogburne]

I have the EXACT same squeal. It's been present since about 15,000 miles and the service manager says he can't hear it. If you find out what it really is let us know...My mileage is eating away at warranty time!!

[BradL]

VetteRacer,

My screech/squeal seemed to be coming from the carrier bearing when I had the two piece shaft - I would let the truck idle down a ranch road and listen and that seemed to be the source. When the two piece was replaced with the one piece, I had no more screech/squeal.

At the time of the two piece I was also getting a lot of slop in the driveline - thump and clump on take-off and slow down.

Now if I could just get the lubrication problem solved on the one piece everthing would be great.

[VetteRacer]

OK, here's the scoop from the dealer.

Squeak in driveline at 35 to 40 (mph)
Transfer case output shaft seal squealing due to lack of lube.
Removed rear drive shaft and lubed seal lips to correct condition. Test drove again. No abnormal noise heard.

Hmm. The truck didn't squeak on the way home, so I guess we'll see after I put some more miles on. I don't have a service manual yet, so I'm not sure what this seal looks like. Does anyone else know if this is a normal maintenance item (i.e. lube every 15,000 miles?). BradL, maybe this is what you were refering to?

[BradL]

VetteRacer,

I thought my noise was the carrier bearing for the two piece shaft, but maybe not.