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Clunk/thud while accelerating/slowing down

nadrojcote

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SouthernSilveradoGuy85 Senior Enthusiast

SouthernSilveradoGuy85

Posted
Posted

I just took my clamps back off temporarily. My truck has always shifted fine, but I just had the clunks. The clamps only got rid of some of the clunks. But to me, I think it did stiffen the ride and it seemed like I could feel more vibrations (just slightly) in my seat when driving locally. Since I took the camps off, I don't feel the slight vibration in the seat anymore.

 

Try torquing the u-bolt nuts. Mine were off spec and had to give all of them at least 1 full turn. So far no clunks. I only got clunks once in awhile, usually when I gave it a lot of throttle.

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sugarjohnson Enthusiast

sugarjohnson

Posted
Posted

I took mine off as well. I already have the NHT and it did ride a little rougher. Jury is out for me?

BOOMER119 Enthusiast

BOOMER119

Posted
Posted

installing them with the wheels on and the truck on the ground means there's some weight on the springs, right? So you can make it tighter with the clamps?

 

I'm heading to Autozone tonight to buy some...

If you jack the truck up under the axle wouldn't that have the same effect as the truck sitting on the tire? The leaf spring is loaded with the weight of the truck either way.

BOOMER119 Enthusiast

BOOMER119

Posted
Posted

I didn't clamp mine after all. What I found out is that while the leafspring ubolts were tight, they still were not torqued to the 78ft/lbs the spec I was given calls for. The driver side nuts were around 60ft/lbs, while the passenger was around 70ft/lbs. So I loosened them all on both sides to relieve the load and allow the leaves to settle, and then retorqued the nuts to 78ft/lbs in the correct pattern. No more clunking/popping. Need to recheck the nuts tonight, but so far, so good!

As I follow this thread it looks live several have found loose ubolts. Is 78 ft lbs the correct torque? What is the correct torque pattern? I will check mine at tire rotation once I have the info.

SouthernSilveradoGuy85 Senior Enthusiast

SouthernSilveradoGuy85

Posted
Posted

As I follow this thread it looks live several have found loose ubolts. Is 78 ft lbs the correct torque? What is the correct torque pattern? I will check mine at tire rotation once I have the info.

 

That's what I torqued mine to because that's what I've read on this thread. You don't have to take the tires off to tighten them so you don't have to wait until the tires are rotated. As for the pattern, I honestly didn't do a certain pattern. I just made sure to TQ both nuts on the same u-bolt before moving to the next one.

CounterMeasure Enthusiast

CounterMeasure

Posted
Posted

 

That's what I torqued mine to because that's what I've read on this thread. You don't have to take the tires off to tighten them so you don't have to wait until the tires are rotated. As for the pattern, I honestly didn't do a certain pattern. I just made sure to TQ both nuts on the same u-bolt before moving to the next one.

 

78ft/lbs is what the dealership told me when they first cranked them down. They said they got more than a full turn on them to torque them to spec.

SouthernSilveradoGuy85 Senior Enthusiast

SouthernSilveradoGuy85

Posted
Posted

 

78ft/lbs is what the dealership told me when they first cranked them down. They said they got more than a full turn on them to torque them to spec.

 

I had to do at least a full turn on all of them too.

nadrojcote Senior Enthusiast

nadrojcote

Posted
  • Author
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I just took my clamps back off temporarily. My truck has always shifted fine, but I just had the clunks. The clamps only got rid of some of the clunks. But to me, I think it did stiffen the ride and it seemed like I could feel more vibrations (just slightly) in my seat when driving locally. Since I took the camps off, I don't feel the slight vibration in the seat anymore.

I figured at some point someone wouldn't like it. At the same time though I haven't notvied anything change. I pay attention to bumps in the road and try to see if I can feel the rear end riding over them rough and the rear still rides smooth.
CalicoJack76 Enthusiast

CalicoJack76

Posted
Posted

Here is a picture of Rockwell American parts number for their shackle kit...

 

Do I need the 2.25 straps or 2.625 ?

 

Guess I can go measure the leaf springs but it's dark out...

post-145457-0-15170300-1435727435_thumb.jpg

post-145457-0-15170300-1435727435_thumb.jpg

post-145457-0-15170300-1435727435_thumb.jpg

post-145457-0-15170300-1435727435_thumb.jpg

sugarjohnson Enthusiast

sugarjohnson

Posted
Posted

I did my ubolts several months ago with no change in the clunkity clunk whatsoever. I will say they were definitely not at spec.

nadrojcote Senior Enthusiast

nadrojcote

Posted
  • Author
Posted

Here is a picture of Rockwell American parts number for their shackle kit...

 

Do I need the 2.25 straps or 2.625 ?

 

Guess I can go measure the leaf springs but it's dark out...

2.625
zert100 Enthusiast

zert100

Posted
Posted

I took mine off as well. I already have the NHT and it did ride a little rougher. Jury is out for me?

I have the "clunk" mostly noticeable when I let off the gas when the truck is in 2nd gear. So driving in parking lots and driving through neighborhoods its very noticeable. The dealer and GM say its normal. I've had 5 different late model GM 4x4's and none of them clunked this bad. pretty sad! I tried clamping the springs and it made no difference on my truck. I'm still trying to figure out what is causing it. I may try a local driveline shop to get their opinion. I will keep this updated if I find out any useful info.

 

sugarjohnson Enthusiast

sugarjohnson

Posted
Posted

 

I have the "clunk" mostly noticeable when I let off the gas when the truck is in 2nd gear. So driving in parking lots and driving through neighborhoods its very noticeable. The dealer and GM say its normal. I've had 5 different late model GM 4x4's and none of them clunked this bad. pretty sad! I tried clamping the springs and it made no difference on my truck. I'm still trying to figure out what is causing it. I may try a local driveline shop to get their opinion. I will keep this updated if I find out any useful info.

 

 

Your description is identical to mine. The clamps however did help somewhat but the clunk was still there but less noticeable. I just did not care for the ride. Also I worried about addition leaf spring stress when I tow my TT which is primarily the job of my truck.

 

On a side note I did just custom tune my truck. Sadly it has not helped the clunk/thud at all. It has cleaned up the power and shifting tremendously and I'm looking forward to a shakedown run with the TT to see if there is a drivability difference while towing. Please keep us updated on the driveline shop.

 

I still wonder if a true traction bar would solve this clunk/thud if it is indeed related axle wrap? I noticed on my BIL new Ram it has traction bars as well as rear sway bar?

nadrojcote Senior Enthusiast

nadrojcote

Posted
  • Author
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I wanted to give you guys the benefit of the doubt and try my truck without them. So I just removed them, tightened up my u-bolts and went for a drive. I can tell the rear doesn't feel as planted, and it does seem a bit softer, but its really hard to tell. I didn't have any clunking for my short drive, but I'm going to keep then off for a while to test it out with just tightening the u-bolts.

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