Horrible noises and ride, HELP!

[DaveLaz]

Hi guys, I lowered my 2006 Yukon SLT 4WD on a crown suspension 2/4 kit that included spindles, rear coils, and shock extenders. I also installed DJM rear trailing arm relocators, proper sway bar end links, and belltech 9513 street performance shocks. When tearing it down I basically had to cut everything out so I ended up also replacing with new LCA’s, UCA’s (with camber adjustment capability) inner/outer tie rod ends, and sway bar end links. Here’s been my experience so far....


At first honestly it felt decent. Some clunks and noises here and there but I figured after settling and getting an alignment it would be better. Also the front wasn’t sitting low enough and I was still on OEM shocks so I figured it would get better after the new shocks came in and I wanted to add lowering keys.


Installed the shocks and I didn’t feel much of a difference but whatever. Got an alignment and it solved a little bit of clunking but the most noticeable one was by the driver side front wheel when taking off from a light.


Had a shop install my keys since I couldn’t get them out. Also had them install new crossmember bushings since I noticed those were shot. $700 in labor plus parts later...the clunk and horrible ride still existed. I ended up having to install one of the OEM keys back into the driver side because with the torsion bolt cranked all the way up, it still sat too low on that side.


This is where I am currently. After MULTIPLE times of lifting the truck, loosening all load points, sitting the truck down and re-torquing them to be sure I’m not missing anything, I’m still having this issue.


Notable mention, the ride is significantly better when first driving after lifting it because it hasn’t settled back down fully. After driving for about 5 miles it settles back down, ride is extremely rough, and that clunk when taking off comes right back in full force.


Guys I seriously need like an open forum of questions, ideas, places where I can drive the truck off a bridge etc.... TIA!

 

[Big Mama]

Sorry you’re having so much trouble. I’m not much help with your model but others will chime in. Have you checked the motor mounts as a source of the clunk? @iamdub @Tonyrodz @kbuskill @Doubeleive may be able to offer more help.

 

[kbuskill]

Engine mounts is a good possible source for the clunk when taking off although the GMT800 platform is less prone to torn mounts than the GMT900 platform.

It is extremely difficult to diagnose things without being present, especially noises.

 

[Doubeleive]

check and lube the shit out of the sway bar bushings (where they mount to the frame D-bushings front & rear), if the sway bar is tight in the bushings it can be the source of clunks, if that solves the issue you may have to make it a habit of doing it every 3-6 months because the lube only last's so long or you may notice it come back after the weather changes or when it rains.

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics, please.

You are already receiving suggestions from the knowledgeable folks on this Forum, and more will chime in. My truck is not a GMT800 platform, so I am not familiar with the details of your truck's suspension. I suggest that you check all of the drivetrain mounts and their bushings on your truck, in addition to your motor mounts, to troubleshoot your clunk noise.

 

[Fless]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics, please.

You are already receiving suggestions from the knowledgeable folks on this Forum, and more will chime in. My truck is not a GMT800 platform, so I am not familiar with the details of your truck's suspension. I suggest that you check all of the drivetrain mounts and their bushings on your truck, in addition to your motor mounts, to troubleshoot your clunk noise.

Don't forget to check the bushings and mounts for the front differential.

 

[Joseph Garcia]

Don't forget to check the bushings and mounts for the front differential.

Thank you @Fless . I was trying to remember the name of that component, when I was replying to the OP's question, but couldn't. I had that clunk, when starting from a red light, and it turned out that the bushings on the mounts of the front differential were shot. I replaced the both entire mounts with new ones with new bushings, and the clunk disappeared.

 

[DaveLaz]

Hey guys thank you SO much for all the help so far. I went ahead and got lubricant and sprayed the D bushings holding the sway bar to the frame and unfortunately I don’t feel a difference. Maybe the lube needs to settle in more? I went ahead while I was at the store and bought new bushings so I’ll throw those in just to indefinitely cross out that as a possible issue. I’ll definitely look into the front differential bushings as well. I definitely notice a clunking when shifting from reverse to drive and vice versa sometimes. Would those bushings and/or motor mounts also cause poor ride quality as well? I’ve had lowered cars and trucks my entire lifetime and nothing has rode over bumps as poorly as this does. I appreciate all the help so far guys keep it coming!!!

 

[Doubeleive]

Hey guys thank you SO much for all the help so far. I went ahead and got lubricant and sprayed the D bushings holding the sway bar to the frame and unfortunately I don’t feel a difference. Maybe the lube needs to settle in more? I went ahead while I was at the store and bought new bushings so I’ll throw those in just to indefinitely cross out that as a possible issue. I’ll definitely look into the front differential bushings as well. I definitely notice a clunking when shifting from reverse to drive and vice versa sometimes. Would those bushings and/or motor mounts also cause poor ride quality as well? I’ve had lowered cars and trucks my entire lifetime and nothing has rode over bumps as poorly as this does. I appreciate all the help so far guys keep it coming!!!

You need to unbolt the D bushings then open the rubber up and put some good grease inside (all over) don't be shy with it, like your gonna pop her other hole, spraying it from the outside won't do much. If that still doesn't help then pop the hood open, start it up and put your foot on the brake, while looking thru the gap under the hood from the drivers area look at the engine while you put it in drive with your foot on the brake and give it some gas and see if the engine moves a lot, it should only budge a little, then do the same in reverse, this test tells you if the motor mounts are bad or not. Since you are lowered inspect the rear sway bar and shocks make sure you are not hitting a shock or something. @Rocket Man any other ideas?

 

[DaveLaz]

You need to unbolt the D bushings then open the rubber up and put some good grease inside (all over) don't be shy with it, like your gonna pop her other hole, spraying it from the outside won't do much. If that still doesn't help then pop the hood open, start it up and put your foot on the brake, while looking thru the gap under the hood from the drivers area look at the engine while you put it in drive with your foot on the brake and give it some gas and see if the engine moves a lot, it should only budge a little, then do the same in reverse, this test tells you if the motor mounts are bad or not. Since you are lowered inspect the rear sway bar and shocks make sure you are not hitting a shock or something. @Rocket Man any other ideas?

Ok so if I’m unbolting the D bushings should I just replace them while they’re off anyways? and then pack them with grease? I’ll check motor mounts tomorrow and report back

 

[Doubeleive]

Ok so if I’m unbolting the D bushings should I just replace them while they’re off anyways? and then pack them with grease? I’ll check motor mounts tomorrow and report back

not unless there torn up or fairly old, just grease slobber grease all over inside and on the bar shaft and slap it back together, while you are under there use a flashlight and look at everything real good, I had a mystery clunk once and it turned out one of the upper control arm bolts was loose just enough to slide up and down and it worn a egg shaped hole in the frame, it was hidden because of the washer the fix was to a weld a really fat washer on the end it worked fine because the bolt has plenty of thread.

 

[DaveLaz]

not unless there torn up or fairly old, just grease slobber grease all over inside and on the bar shaft and slap it back together, while you are under there use a flashlight and look at everything real good, I had a mystery clunk once and it turned out one of the upper control arm bolts was loose just enough to slide up and down and it worn a egg shaped hole in the frame, it was hidden because of the washer the fix was to a weld a really fat washer on the end it worked fine because the bolt has plenty of thread.

Copy that, thanks!

 

[DaveLaz]

Hey guys, quick update. I haven’t greased the sway bar mounts yet however I did unbolt the end links just to see how the susp would react to no sway bar at all. The harsh ride and clunk when taking off reduced however did not go away. I’ll be greasing up the mounts later and reattaching the links but I did notice something. The torsion bar fitting/knuckle in the LCAs seem unusually large. Picture fitting a 17mm socket on a 16mm head bolt. Is that normal for everyone or are the LCAs that they sent me not correct?

 

[Byoung1330]

Hi guys, I lowered my 2006 Yukon SLT 4WD on a crown suspension 2/4 kit that included spindles, rear coils, and shock extenders. I also installed DJM rear trailing arm relocators, proper sway bar end links, and belltech 9513 street performance shocks. When tearing it down I basically had to cut everything out so I ended up also replacing with new LCA’s, UCA’s (with camber adjustment capability) inner/outer tie rod ends, and sway bar end links. Here’s been my experience so far....


At first honestly it felt decent. Some clunks and noises here and there but I figured after settling and getting an alignment it would be better. Also the front wasn’t sitting low enough and I was still on OEM shocks so I figured it would get better after the new shocks came in and I wanted to add lowering keys.


Installed the shocks and I didn’t feel much of a difference but whatever. Got an alignment and it solved a little bit of clunking but the most noticeable one was by the driver side front wheel when taking off from a light.


Had a shop install my keys since I couldn’t get them out. Also had them install new crossmember bushings since I noticed those were shot. $700 in labor plus parts later...the clunk and horrible ride still existed. I ended up having to install one of the OEM keys back into the driver side because with the torsion bolt cranked all the way up, it still sat too low on that side.


This is where I am currently. After MULTIPLE times of lifting the truck, loosening all load points, sitting the truck down and re-torquing them to be sure I’m not missing anything, I’m still having this issue.


Notable mention, the ride is significantly better when first driving after lifting it because it hasn’t settled back down fully. After driving for about 5 miles it settles back down, ride is extremely rough, and that clunk when taking off comes right back in full force.


Guys I seriously need like an open forum of questions, ideas, places where I can drive the truck off a bridge etc.... TIA!

Was the clunk there before lowering? And I see u said u changed the Lca. Did u just do the ball joint or the whole arm? Also mine is a 04 tahoe with 3/6 drop. I had the same issue. Loud clunk. Sounded like it was from the middle or front somewhere. I finally found what mine was. When I put my drop spindles on (mcgaughys) I messed up my driver side lower ball joint. So replaced it. It was a pain to press new one in. So with having new ball joint on that side I wanted the other side new. Didn’t want to do the press thing again so I changed the whole lower arm with ball joint already installed. So after installing I started getting that loud clunk. I ended up replacing my whole front suspension just cuz I wanted it all new. Not cuz the clunk. I went with moog on everything except upper a arms. They are ac delco. Well when I messed that ball joint up I had got a cheap one put in it. I didn’t like that as they have a lot of load. So I ordered 2 ac delco ones. Pressed into my arm an then the other side that I had changed the whole arm I ended up pressing that new ball joint in my oem control arm an putting it back on an not using the new one I had installed. Clunk was gone. I think where the torsion bar went into the after market arm it had slop in it or something an it was the torsion bar clunking. Hasn’t done it since

 

[Byoung1330]

I think the after market arm hex slot that the torsion bar goes in was slightly bigger. It made it pop an make all kinds of sounds when braking or taking off.

 

[Rocket Man]

I don’t have much to add other than check the sway bar end links and maybe put jg on jack stands and pull the front wheels, then put a floor jack on each knuckle and run it up and down looking for sounds or signs of trouble. Also those Belltech shocks aren’t that great, should be running Bilstein’s.

 

[DaveLaz]

I think the after market arm hex slot that the torsion bar goes in was slightly bigger. It made it pop an make all kinds of sounds when braking or taking off.

I found a TSB on body mount insulators so I’ll be replacing those as soon as those come in. I’ll also be re-indexing the torsion bars as I noticed they are rotated counter-clockwise by one hex. If either of these don’t work I’ll be replacing the LCAs as a last resort. I appreciate your feedback, it gives me a little hope for my suspicions on the hex opening.

 

[DaveLaz]

I don’t have much to add other than check the sway bar end links and maybe put jg on jack stands and pull the front wheels, then put a floor jack on each knuckle and run it up and down looking for sounds or signs of trouble. Also those Belltech shocks aren’t that great, should be running Bilstein’s.

Unless the belltechs are filled with concrete, I highly doubt that’s the problem. The ride is unbearable honestly. And I don’t mind switching to Bilsteins in the future after I get it in a much better state.

 

[Rocket Man]

Unless the belltechs are filled with concrete, I highly doubt that’s the problem. The ride is unbearable honestly. And I don’t mind switching to Bilsteins in the future after I get it in a much better state.

Well hate to tell you but shocks are important to ride quality. The Bilsteins you need are the 4600’s. The rest of my answer stands as well. I mean, you came here asking for help, correct?

 

[Byoung1330]

I had belltech sp an didn’t like them. I run the bilstein 4600 now. They are long but compress a lot. They work great on my Tahoe as low as it is