Frame "Jounce"?

[crash12888]

Hi all, I just joined the site and looking for help. I just purchased a 06 Silverado 4dr 4X4. I have had a vibration in the truck since day one (not in steering wheel) that comes and goes or hit a bump and vibrates for the next 100 yards. I took it back to dealer for rebalance and alignment, still not good. Dealer then put new tires(more Bridgstone) on it saying it might by flat spots from sitting on lot. still not right. Now they say it is "Frame Jounce" due to a redesign in the frame for more flex. I asked to drive another 06. I drove service managers personal 05 and another new 06, both same body style and both had the belly shaking vibration. He said I will get used to it. NOT for what I paid for it I won't. Anyone heard of this or got any suggestions? I'm swapping the wifes wheels and Michelins this weekend to see what happens. Sorry so long winded and thanks for any help. Mitch Samuel, perfecting bellybutton jumping jacks while driving.....

[shorepatrol2]

That sucks , I hate vibrations , I could never get used to it , I feel for you if it's a design flaw , I agree too much money for these trucks to have to deal with things like that , that are unfixable, Good luck , hope it works out for you

[pm26]

Hi all, I just joined the site and looking for help. I just purchased a 06 Silverado 4dr 4X4. I have had a vibration in the truck since day one (not in steering wheel) that comes and goes or hit a bump and vibrates for the next 100 yards. I took it back to dealer for rebalance and alignment, still not good. Dealer then put new tires(more Bridgstone) on it saying it might by flat spots from sitting on lot. still not right. Now they say it is "Frame Jounce" due to a redesign in the frame for more flex. I asked to drive another 06. I drove service managers personal 05  and another new 06, both same body style and both had the belly shaking vibration. He said I will get used to it. NOT for what I paid for it I won't. Anyone heard of this or got any suggestions? I'm swapping the wifes wheels and Michelins this weekend to see what happens. Sorry so long winded and thanks for any help.  Mitch Samuel, perfecting bellybutton jumping jacks while driving.....

 

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I have the same truck (Z71) and I do not have this type of shake, but I found out that the truck tends to run smoother with some weight in the bed. Try 300 lbs worth of sandbags in the bed over the rear axle and see what happens. If nothing, go all the way up to about 1000 lbs to see if the problem disappears.

[shorepatrol2]

I have the same truck (Z71) and I do not have this type of shake, but I found out that the truck tends to run smoother with some weight in the bed. Try 300 lbs worth of sandbags in the bed over the rear axle and see what happens. If nothing, go all the way up to about 1000 lbs to see if the problem disappears.

 

That's ridiculous to have to go through that to have a decent ride after paying 30G plus for a truck

[pm26]

I have the same truck (Z71) and I do not have this type of shake, but I found out that the truck tends to run smoother with some weight in the bed.  Try 300 lbs worth of sandbags in the bed over the rear axle and see what happens.  If nothing,  go all the way up to about 1000 lbs to see if the problem disappears.

 

That's ridiculous to have to go through that  to have a decent ride after paying 30G plus for a truck

 

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And what do you suggest as an alternative? At least he will have some idea if the probelm is truly the beam shake, not some other issue.

[GM-Tech]

That's ridiculous to have to go through that  to have a decent ride after paying 30G plus for a truck

 

Well, it is a truck, afterall, not a Coupe Deville. What about the construction companies, landscapers, plumbers, etc., that buy the truck to use as a truck. They'd be complaining if the thing couldn't handle the workload. I guess there are going to be some tradeoffs between utility and comfort. If you wanted a car ride, you should have bought a car.

[shorepatrol2]

Vibration is unacceptable no matter what you are driving or what conditions you driving under. Stiff or bad ride is another story

[crash12888]

Thanks for the input guys, I have owned trucks my whole life and do know the difference between a stiff ride and bad ride. This is really a bad riding truck. My 95 gmc 1500 w/BFGs rode very well. I was just curious, does anyone else with this truck have similar issues? Can't find any info on frame jounce on the web other than it is a combination of the words "to jar" and "to bounce". go figure

can someone give more details about "beam shake"?

[GM-Tech]

Don't know if this helps you...

 

 

Subject: Suspension Vibration or Frame Beaming at 40-60 MPH (64-80 km/h) - keywords front rear shake shock spring tire #PIT3009D - (09/14/2006)

 

 

Models: 1999-2007 Chevrolet Silverado Classic

 

1999-2007 GMC Sierra Classic

 

 

 

 

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This PI is being updated to provide additional fix information and parts available. Please discard PIT3009C.

 

 

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The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

 

Condition/Concern:

Beam shake vibration is usually felt in the seat and occurring at speeds between 40-50 mph (64 - 80 km/h). Hertz readings using an EVA tool are normally between 8-24 Hz. This condition is most common on extended cab and crew cab models but has also been noted in other models.

 

Recommendation/Instructions:

The severity of beam shake may vary from vehicle to vehicle. To determine if the concern is beam shake, please perform the following:

 

Test drive vehicle to confirm the condition. A beam shake condition will usually respond to concrete type pavements more than asphalt, so the vehicle should be driven over both surfaces if possible.

Place 200-500 pounds in the pickup bed between the closed tailgate and the wheel wells. A beaming condition should dissipate.

Note: Tires with excessive Radial Force Variation (RFV) or out-of-roundness can intensify the frame beaming concern. The following radial force variation numbers should be used as a guide:

 

P-Metric tires (2WD 1500)

12 lbs or less

 

P-Metric tires (all others)

24 lbs or less

 

LT-tires

30 lbs or less

 

 

If the concern is determined to be beam shake, this is a characteristic of the vehicle and currently no repair attempts should be made. With your help in the use of the Field Product Reporting process GM Engineering is currently developing an enhancement to the body mounts to reduce this concern on the 1500 Models. On going testing has pushed the timing of these mounts to the first half of 2007. There will be no enhancement made to the 2500 and 3500 models. At this point no more Field Product Reports are needed and thanks for your help.

 

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

 

 

 

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

 

 

© Copyright General Motors Corporation. All Rights Reserved.

[crash12888]

GM-tech,

Being a new member here for just hours, I don't know personality traits and feel akward posting this but the comment "If you wanted a car ride, you should have bought a car" is the same attitude I am getting from the dealer. I never mentioned I wanted a Caddy suspension under my truck, My concern is that if I bought a 3500 dually it would ride like a dually but should not vibrate. With all due respect, you missed the original question.

[GM-Tech]

GM-tech,

    Being a new member here for just hours, I don't know personality traits and feel akward posting this but the comment "If you wanted a car ride, you should have bought a car" is the same attitude I am getting from the dealer. I never mentioned I wanted a Caddy suspension under my truck, My concern is that if I bought a 3500 dually it would ride like a dually but should not vibrate. With all due respect, you missed the original question.

 

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You are certainly entitled to your opinion.

[Wingnut]

I figure that if it were actually a problem with the truck, it would do it all the time, on all surfaces, at all speeds. But it doesn't. To me, it's all about the design and construction method of the concrete (mine VERY rarely did it on asphalt) in relation to the wheelbase on the truck. Something about the frequency of the slabs and how the truck handled the breaks at certain speeds. My reg-cab would do it once in a blue moon, but my ex-cab would shake your fillings out on certain sections of highway at 70mph.

 

Every ex-cab and crew I've ridden in (all brands) in the last 10 years have had this problem to some extent on certain sections of highway.

 

/.02

[mmmikkke]

I felt double crossed that something I assumed about the vehicle, that it rode reasonably well on all pavement types, was not true and the dealer (and the manufacturer) did nothing to alert me to the new deterioration in ride quality. But actually it's a part of a pattern, and it's not going away. From now on, I'm going to have to do more thorough research before my next purchase.

 

Web sites like this can set the flags, then we have to check them out. My red flags:

1. Can't disable the auto power locks on 2005 models.

2. 4L80E trans upshifts from 1 to 2 at 2800 rpm even if you've selected 1. So it's not "1", it's "1-ish".

3. "2" is "2" when starting from a stop. Used to be 1, then 2.

4. Beam shake is annoying to unacceptable depending on model.

5. Perimeter lighting (energizing parking lights and backup lights when unlocking the doors at night with the key fob) can't be disabled. What a stoooopid idea!

6. Power seats articulate awkwardly.

7. Get the steering wheel controls, no matter what, you'll be glad you did.

 

Where was the salesman guiding me on all 7 points? Out to lunch!

 

Ok, anyway, note that the service bulletin states that the extra weight should be placed BEHIND the rear axle instead of directly over it.

[Sierra 05]

I felt double crossed that something I assumed about the vehicle, that it rode reasonably well on all pavement types, was not true and the dealer (and the manufacturer) did nothing to alert me to the new deterioration in ride quality.  But actually it's a part of a pattern, and it's not going away.  From now on, I'm going to have to do our more thorough research before my next purchase. 

 

Web sites like this can set the flags, then we have to check them out.  My red flags:

1. Can't disable the auto power locks on 2005 models.

2. 4L80E trans upshifts from 1 to 2 at 2800 rpm even if you've selected 1.  So it's not "1", it's "1-ish".

3. "2" is "2" when starting from a stop.  Used to be 1, then 2.

4. Beam shake is annoying to unacceptable depending on model.

5. Perimeter lighting (energizing parking lights and backup lights when unlocking the doors at night with the key fob) can't be disabled.  What a stoooopid idea!

6. Power seats articulate awkwardly.

7. Get the steering wheel controls, no matter what, you'll be glad you did.

 

Where was the salesman guiding me on all 7 points?  Out to lunch!

 

Ok, anyway, note that the service bulletin states that the extra weight should be placed BEHIND the rear axle instead of directly over it.

 

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Well, as for diabling perimeter lights, on a GMC you can!

[pm26]

Is the truck in the original post a Z71 or a regular crew cab 4X4/ The reason I ask is because the Z71 has different shock absorbers, which may alter tthe beam shake characteristics.

 

In fact, here is what I would experiment with to lessen the unpleasant effects of the beam shake:

 

1. Try diffferent softer riding shock absorbers. This is relatively cheap and easily reversible if no improvement noted.

 

2. Front torsion bars can be adjusted too stiff. this will have the effect of limiting suspension travel and harsher ride. You can try experimenting with the torsion bars and lower the front end of the truck a little. This may help. I had a 95 Nissan 4X4 SE V6 pickup that came factory equipped with huge (for this truck) LT 31X10.5 tires. To make tthe room for the tires, they wound up the torsion bars and raised the front end about 2 inches higher than on a regular truck. This made for an extremely stiff ride, and occassionally the whole front end of the truck would shake after hitting a bump. I switched to smaller P23575R15 tires, which were more appropriate for this truck, and the ride improved immediately, even without adjusting the front torsion bars.

Did the dealer check the truc's alighment, including the riding height of the front end?

 

3. Lowering the tire pressure a little would make the beam shake less pronounced too. I am not saying to go below the recommended 35 psi cold, but not above either.

 

4. And as mentioned, some weight in the truck bed will definitely help.