Driveline noise

KurtMcMouth · October 7, 2004

I have a 2500HD (2 piece drive shaft) with a DJM 3/5 drop. After installing the drop, there is some drive line noise (almost sounds like a u-joint going out) only between about 62 mph and 66 mph. I suspect the rear drive shaft might be the culprit as it is now at a different angle than before.

Anyone have this issue before? I realize my application is rare...

Shaners · October 7, 2004

You might need to change the rear pinion angle to accomodate your new suspension mods.

KurtMcMouth · October 7, 2004

Yeah, thats what i was thinking, but I would essentially have to move the front-most end of the rear drive shaft up. Not sure how to do that.

I was actually thinking of putting a one-piece drive shaft on the truck. Do all 2500HD crew cab short beds come with a 2 piece drive shaft or did i just get unlucky?

Shaners · October 8, 2004

My truck had a 2-piece (all '01 crewcab shortbeds came this way). It was replaced under warranty with a 1-piece unit similar to the ones found in the '02s and up.

I believe the way the pinion angle is checked/aligned is with shims. I'm not positive about this though.

KurtMcMouth · October 8, 2004

My truck had a 2-piece (all '01 crewcab shortbeds came this way). It was replaced under warranty with a 1-piece unit similar to the ones found in the '02s and up.

I believe the way the pinion angle is checked/aligned is with shims. I'm not positive about this though.

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Yeah, this is what i was looking for. But...how did you get them to approve warranty work for this? Was something horked up? I'm guessing they will tell me that mine is not under warranty because of the lowering kit I put on it.

Shaners · October 8, 2004

I had a driveline vibration when taking off. I believe the technical term is "launch Shudder", and there is a TSB for it. The vibration was cause by the carrier bearing, which is eliminated with the driveshaft replacement.

KurtMcMouth · October 11, 2004

Okay, I'm a dumb rookie, what is TSB? Here's the dilemma. The dealer is likely going to tell me I've voided my warranty with the lowering kit. I'm trying to see if there is a way to get this handled by a recall or something of that nature. How does a TSB relate to a recall, or do they?

Shaners · October 11, 2004

A TSB is a Technical Service Bulliten that GM puts out to their service garages.

When it appears that their is a trend of a certain problem, GM writes the bulliten to give the service dept the proper fix without having to go through a diagnosis.

Since it isn't safety related, it is not considered a "Recall".