Clunk/thud while accelerating/slowing down

[nadrojcote]

Yep I have tightened mine u-bolts down x 2 with no change. I also tried the clamps which helped but did not solve it. The description above is spot on. I can replicate it very time. Driving through subdivision 1-3. Accelerate light and then let of gas=clunk. Almost always when letting off never getting back on gas. I had it looked at long ago they said "no problems" imagine that.

 

I have custom tune now and no difference. He even verified that he did not really change shift pressures etc. Its the same with the tune as without. I will say the the truck is much quicker now!

It's sounds like the same issue I was having, clamping and tighting u-bolts both separately fixed it for the most part. It still does it. Now it doesnt make my entire truck sound like its going to thud itself apart anymore though. I have been hearing a sound coming from my transmission/transfer case lately too, its more of a clank though and it happens in the same scenario. Accelerating and then letting off the gas.

 

I'm at the point now that I am done working on my truck. It looks the way I want it to, and I'm sick of spending money and time on it. If I have one more major issue with it I'm trading it in.

[iCryWheniGoPoop]

I tightened mine to 78 ft lbs and eliminated most of my noise and like everybody else, mine turned 2 full turns before meeting correct torque specs. Curiosity got to me so I started looking up specs on the actual torque for that size spring bolt and found it to be capable of at least 100ft lbs so I torqued mine to 90 and eliminated all my leaf spring noise. I'm not suggesting this, I'm just telling you what I did. I also found some good reading for you guys if you want to check this out.http://www.rnhspring.com/Ubolts.html

Oh and FYI... Mine was making a lot of noise since I'm putting mine through the wringer testing and tuning.

Update, been driving all day and am still hearing it ocassionally. I could easily say that I have eliminated 90% of the noise. This one seems like it may be coming more from driveline or yoke like others have mentioned.

[nadrojcote]

Update, been driving all day and am still hearing it ocassionally. I could easily say that I have eliminated 90% of the noise. This one seems like it may be coming more from driveline or yoke like others have mentioned.

 

 

Yup same for me, clamps eliminated about 99% of noises, tightening u-bolts alone reduced about 90% of noises.

[Cove9]

I have noticed that there is one clamp towards the front holding the top and middle leaf from moving laterally, but all of the popping noise is coming from the rear where the middle leaf is rubbing side to side against the top leaf. does adding a clamp 5 inches from the front of the axel cause any bad long term effects to the vehicle.

[Jackseric]

Well, count mine as another that had loose u-bolts. Well, not loose, but it took 2 full turns of nearly all the of them to get to 78 lbs. Funny thing is, I've had my truck in to the dealership, with a complaint about rear suspension noise. They told me they went over everything and everything checked out per spec. Crossing my fingers for tomorrow's first drive to see if this quiets the bucket of bolts hiding under my trucks bed.

[hotrodz37]

I just checked mine as well and got 2 full turns out of them.

 

Question for you guys, just racking my brain here. Did any of you have the highway vibration and do this and it help? I'm sure torquing these to proper spec can't hurt at all but only help, but wondering if the u-bolts being under tightened might be one of the contributing problems to the highway vibration for many.

[SouthernSilveradoGuy85]

I just checked mine as well and got 2 full turns out of them.

 

Question for you guys, just racking my brain here. Did any of you have the highway vibration and do this and it help? I'm sure torquing these to proper spec can't hurt at all, but wondering if this might be one of the contributing problems to the highway vibration for many.

 

 

Too some people it might have been the reason. All I had was the clunk once in awhile, no vibrations at all at any speed. The clunk in my situation was just axle wrap. So far torquing the u-bolt nuts completely fixed the clunk, haven't heard a clunk since doing it maybe a month ago give or take. Either the TQ wrenches they were using on the assembly line wasn't calibrated or they simply set them at the wrong ft/lbs and GM changed it after the fact since I read it's 78 ft/lbs so either it changed or their TQ wrenches aren't calibrated.

[nadrojcote]

I think theres just too much stress on the u-bolts and they actually need to be tighter than factory spec. 78 ft lb isn't much especially seeing how the leafs flex so much.

[SouthernSilveradoGuy85]

I think theres just too much stress on the u-bolts and they actually need to be tighter than factory spec. 78 ft lb isn't much especially seeing how the leafs flex so much.

 

I'm going by what someone said that they were told from a dealer that they need to be 78 ft/lbs. I don't know if it seems right, but the lug nuts on these 6 lug GM trucks have been 140 ft/lbs for a long time (my '98 manual said 140 and my '14 manual said 140 so I just assume that any 6 lug full size GM truck from at least 88 has the lug TQ spec of 140) and I think lugs and rims take more impact hit and side load than axle u-bolts. I could be wrong, just what I'm thinking.

[nadrojcote]

 

I'm going by what someone said that they were told from a dealer that they need to be 78 ft/lbs. I don't know if it seems right, but the lug nuts on these 6 lug GM trucks have been 140 ft/lbs for a long time (my '98 manual said 140 and my '14 manual said 140 so I just assume that any 6 lug full size GM truck from at least 88 has the lug TQ spec of 140) and I think lugs and rims take more impact hit and side load than axle u-bolts. I could be wrong, just what I'm thinking.

you're right, they do take more stress, but there's also 12 of them on the rear axle compared to 8 nuts on the u-bolts. There also may have been a manufacturing issue with the u-bolts and they may have had a little bit of lubricant left on them. This happened with my lug nuts and they loosened off. Had to clean them with brake cleaner.

[bowtiemark]

Does anyone have a link or part number to the bolts/bolts. I’m having this real annoying clunk when accelerating and coming to a stop/braking, coming from the right side of the cab. Rather give this a try before I go to the stealership and see what bs they give me.

[bowtiemark]

On 5/28/2015 at 5:01 PM, CounterMeasure said:

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!

Want to try this on my off day, how is this holding up so far? My 14 with 72k miles is making an insane clunking noise when slightly accelerating. Before I spend days and money at the dealership want to see if there is another way to fix.

[CounterMeasure]

12 minutes ago, bowtiemark said:

Want to try this on my off day, how is this holding up so far? My 14 with 72k miles is making an insane clunking noise when slightly accelerating. Before I spend days and money at the dealership want to see if there is another way to fix.

Considering my reply is 3.5 years old, it was fine until I traded in the POS last September. My '20 Ram Limited is a night and day improvement over that Denali in terms of build quality, and to this point, reliability.

 

 

[bowtiemark]

On 6/8/2015 at 9:00 PM, nadrojcote said:

 

 

 

 

Just like in this picture

Picture isn’t showing, the side closer the rear end, or by the rear doors? Thank you