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