2006 Sierra VortecMax Drive-Line Noise

hdfat2002 · October 13, 2006

Greetings to the Forum and our resident GM Tech.

I have a 2006 GMC Sierra Crew-Cab 1500 2WD with the VortecMax Performance Package, A/T, and automatic locking differential. It has a strange noise, seemingly from the driveline, on moderate acceleration. The noise is NOT there on light acceleration, nor on hard acceleration--but at 25-40% throttle (estimated) it is prevalent.

It kinda sounds like someone taped a playing card to one of the wheels--for every revolution, there is a little fluttery noise that is hard to describe. It is rhythmic and follows vehicle speed. It goes away above about 35MPH and only seems to happen in first and second gear.

Any thoughts? Is this a normal condition? There doesn't seem to be anything WRONG with the truck--it performs admirably and is a pleasure to drive. But my passengers ask "What is that?" and I find myself a little embarassed.

I am debating taking it in for a warranty repair, but I'd just as soon avoid that if it is normal. A nice cat-back exhaust would easily drown out the sound (the radio does, as it is). And it has occurred to me that it may go away after I allow the truck to "break in." It only has 1020 miles so far.

Thanks in advance for you help!

-Fat

hdfat2002 · October 15, 2006

Greetings to the Forum and our resident GM Tech.

I have a 2006 GMC Sierra Crew-Cab 1500 2WD with the VortecMax Performance Package, A/T, and automatic locking differential. It has a strange noise, seemingly from the driveline, on moderate acceleration. The noise is NOT there on light acceleration, nor on hard acceleration--but at 25-40% throttle (estimated) it is prevalent.

It kinda sounds like someone taped a playing card to one of the wheels--for every revolution, there is a little fluttery noise that is hard to describe. It is rhythmic and follows vehicle speed. It goes away above about 35MPH and only seems to happen in first and second gear.

Any thoughts? Is this a normal condition? There doesn't seem to be anything WRONG with the truck--it performs admirably and is a pleasure to drive. But my passengers ask "What is that?" and I find myself a little embarassed.

I am debating taking it in for a warranty repair, but I'd just as soon avoid that if it is normal. A nice cat-back exhaust would easily drown out the sound (the radio does, as it is). And it has occurred to me that it may go away after I allow the truck to "break in." It only has 1020 miles so far.

Thanks in advance for you help!

-Fat

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Any Forum members heard of this issue before? I'm just about certain the noise is coming from the rear-end. Seems to be torque-dependent. Gotta be something to do with the auto-locker. We'll see what happens when I take her in next week...

-Fat

Brain · October 17, 2006

It might be the torque converter causing this noise. If the noise goes away when the converter locks up in 3rd and 4th that is the problem. See what the dealer says next week

hdfat2002 · October 18, 2006

It might be the torque converter causing this noise. If the noise goes away when the converter locks up in 3rd and 4th that is the problem. See what the dealer says next week

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Took the rig into Reynolds GMC (West Covina, CA) yesterday. No word yet...

-Fat

hdfat2002 · October 19, 2006

It might be the torque converter causing this noise. If the noise goes away when the converter locks up in 3rd and 4th that is the problem. See what the dealer says next week

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Took the rig into Reynolds GMC (West Covina, CA) yesterday. No word yet...

-Fat

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OK, so the word is the noise is coming freom the third-member. The Service Advisor said something "wasn't machined correctly" from the factory and that they had ordered the parts. It wasn't clear to me--based on his description--if it was the pinion, the ring gear, or the carrier that had the trouble. I guess I'll know when I see the RO when they are done.

Supposed to be home again Friday. I'll update you all then.

-Fat

hdfat2002 · October 19, 2006

It might be the torque converter causing this noise. If the noise goes away when the converter locks up in 3rd and 4th that is the problem. See what the dealer says next week

<{POST_SNAPBACK}>

Took the rig into Reynolds GMC (West Covina, CA) yesterday. No word yet...

-Fat

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OK, so the word is the noise is coming freom the third-member. The Service Advisor said something "wasn't machined correctly" from the factory and that they had ordered the parts. It wasn't clear to me--based on his description--if it was the pinion, the ring gear, or the carrier that had the trouble. I guess I'll know when I see the RO when they are done.

Supposed to be home again Friday. I'll update you all then.

-Fat

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Word is, she's getting a Ring & Pinion AND a Carrier.

I'll update you all with how it turned out tomorrow.

-Fat

hdfat2002 · October 21, 2006

It might be the torque converter causing this noise. If the noise goes away when the converter locks up in 3rd and 4th that is the problem. See what the dealer says next week

<{POST_SNAPBACK}>

Took the rig into Reynolds GMC (West Covina, CA) yesterday. No word yet...

-Fat

<{POST_SNAPBACK}>

OK, so the word is the noise is coming freom the third-member. The Service Advisor said something "wasn't machined correctly" from the factory and that they had ordered the parts. It wasn't clear to me--based on his description--if it was the pinion, the ring gear, or the carrier that had the trouble. I guess I'll know when I see the RO when they are done.

Supposed to be home again Friday. I'll update you all then.

-Fat

<{POST_SNAPBACK}>

Word is, she's getting a Ring & Pinion AND a Carrier.

I'll update you all with how it turned out tomorrow.

-Fat

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So the Service Advisor called me today. He said the truck was all done (meaning the new third-member had been installed) and that the truck now has "an even louder noise than before."

He said they are ordering a drive-shaft and that it will be in some time next week.

I'm thinking it's gonna end up needing a trans. Those 4L70E transmissions are a fairly new piece--wouldn't surprise me if there weas a production hiccup.

This is a real bummer! I've only HAD the truck three-weeks as of yesterday, and 5 days of that it has been in the dealership with a problem! Not to mention the driveshaft won't be in until the middle of next week, so it will be at least that long before they find the real problem! Then, they'll have to order something ELSE! By the time I get my truck back, I'll bet it will have been in their custody a good three weeks!

Oh well. Hopefully their techs are better at R&R than they are at diagnosis.

More updates when I have them...

-Fat

GM-Tech · October 21, 2006

Your initial description sure doesn't sound like any rear end noise I've heard. Ring and pinion noises are usually most noticeable around 45-50 mph, but you say yours goes away above 35. It also doesn't matter what gear you're in. However, they usually are sensitive to the level of acceleration, deceleration, so that's the only thing I'm seeing that fits.

Setting up a ring and pinion is really an art form. Not a lot of guys can put one together and have it be dead silent. There's one guy in our shop that's an expert at it, and he's the only one I'd trust to set one up. I wouldn't even trust myself.

I don't see how a driveshaft is going to make this noise either, but without actually hearing the noise, that's really hard to say.

I hate to say anything bad about the dealer or the techs without knowing all the details, but it sounds like they're using the shotgun method of repair.

hdfat2002 · October 22, 2006

Your initial description sure doesn't sound like any rear end noise I've heard. Ring and pinion noises are usually most noticeable around 45-50 mph, but you say yours goes away above 35. It also doesn't matter what gear you're in. However, they usually are sensitive to the level of acceleration, deceleration, so that's the only thing I'm seeing that fits.

Setting up a ring and pinion is really an art form. Not a lot of guys can put one together and have it be dead silent. There's one guy in our shop that's an expert at it, and he's the only one I'd trust to set one up. I wouldn't even trust myself.

I don't see how a driveshaft is going to make this noise either, but without actually hearing the noise, that's really hard to say.

I hate to say anything bad about the dealer or the techs without knowing all the details, but it sounds like they're using the shotgun method of repair.

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Thanks for your reply, GM-Tech.

I am a Toyota guy by trade; GM guy by enthusiasm only. That said, Automotive Technology may be different from one manufacturer to another, but stuff like this is realitively elementary. Something is making a noise, and there's a reason. Where the noise is coming from needs to be identified before throwing parts at it.

Having said that, I know what it's like to be the tech responsible for fixing an obscure problem. I am just going to relax and await their repair like a good, friendly customer.

While I don't personally approve of the "shotgun" approach, I'll just be glad to have my truck back without them screwing it up. It's brand new!

Cheers,

-Fat

hdfat2002 · October 25, 2006

Your initial description sure doesn't sound like any rear end noise I've heard. Ring and pinion noises are usually most noticeable around 45-50 mph, but you say yours goes away above 35. It also doesn't matter what gear you're in. However, they usually are sensitive to the level of acceleration, deceleration, so that's the only thing I'm seeing that fits.

Setting up a ring and pinion is really an art form. Not a lot of guys can put one together and have it be dead silent. There's one guy in our shop that's an expert at it, and he's the only one I'd trust to set one up. I wouldn't even trust myself.

I don't see how a driveshaft is going to make this noise either, but without actually hearing the noise, that's really hard to say.

I hate to say anything bad about the dealer or the techs without knowing all the details, but it sounds like they're using the shotgun method of repair.

<{POST_SNAPBACK}>

Thanks for your reply, GM-Tech.

I am a Toyota guy by trade; GM guy by enthusiasm only. That said, Automotive Technology may be different from one manufacturer to another, but stuff like this is realitively elementary. Something is making a noise, and there's a reason. Where the noise is coming from needs to be identified before throwing parts at it.

Having said that, I know what it's like to be the tech responsible for fixing an obscure problem. I am just going to relax and await their repair like a good, friendly customer.

While I don't personally approve of the "shotgun" approach, I'll just be glad to have my truck back without them screwing it up. It's brand new!

Cheers,

-Fat

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It's Fixed!

The dealer installed the drive-shaft and, as we all thought, it didn't fix it. The Service Manager got involved and had the tech completely strip the rear axle assembly because the noise was definitley coming from there (they were using chassis-ears).

Lo and behold, the pinion bearing showed signs of having been installed with a punch--there was a little ding on the cage and on the outer race. Previously, the dealer had installed a new carrier and ring gear--but left the original pinion in place. So this was not seen before.

Long story short, the tech had a whale of a time figuring this all out, but it turned out to be a minor item (although it was a big job). So all the previously replaced parts went back to the parts bin and my rear-end got a new bearing and now she drives smooth as buttered glass.

Thanks to all the Forum members for listening.

-Fat

Again, a happy VortecMax driver!