New problem (intermittent clunk / thump directly under arm rest / center console)

[Happy Hummer]

New problem (intermittent clunk / thump directly under arm rest / center console) .:sigh:

So as the title states this odd issue just started Tuesday of this week. At first I just thought it was stuff in my cooler banging around. Nope! I moved the cooler out and still have this issue. You can feel the thump, clunk right through the floor.

I got under the 07 H3 (84K miles) when I got home from business today and had a thorough look.
Nothing seems out of place. All items seem tight. I grabbed, tugged and pulled. As the title states this is an intermittent issues. I can be driving along and it will do the clunk, thump a handful of times and then for blocks it will be smooth and quiet.

The front diff bushing was replaced a couple years ago. All the shocks were replaced too. Lol! This H3 has had awesome maintenance as I'm a picky prick for preventative measures. I use it for biz weekly so it has to run....

The Back drive shaft was rebuilt at the beginning of the spring and all the brakes are maintained and working.

Are there any known issues with Hummer H3 trans mounts or torsion spring mounts failing or such???

 

[Happy Hummer]

Well I came right home to the garage today and got started. Took the rear drive shaft off and checked again. Greased the splines and the outer of the spline housing. Pulled the front drive shaft out completely. Other than the boot having a bit of mild dry rot there really wasn't anything. Of course there is one thing that kind of made me go "hmm?" The CV end felt kind of tight at its most flexed position when swirling it around. I'm not certain if that is normal. Changed the T-case fluid and took it for a test ride.

I lubed the pizz out all the mounts and shift linkage and anything that looked like it needed it.

 

[rascole]

My first thought would be the front drive shaft CV going bad.

 

[alrock]

I would double check that diff bushing. After that I'd look at motor mounts, side diff bushings, exhaust hangars (though that's typically a clang or vibration), and whether you ran over any Oompa Loompas.

Trans mount lasts a long time. Torsion bar "mounts" are only the front lower control arm bushings. Could be a clunk though is often a steering wheel off center or pulling when braking.

 

[Happy Hummer]

I looked each exhaust hanger over twice while I was under the H3 today, yesterday so I'm at least a little more confident they all seem intact. But hey I'm humane and we are known to make mistakes lol.
The Diff mount also had my attention because I to felt like it was the definite place to spend some time but it seems tight and working correctly.
I've never changed the side bushings on the mount for the diff so that is a place to check.
Like wise the motor mounts are the same as when I bought Happy 10+ yrs. ago.
Great suggestions and I appreciate everyone's help and guidance. Thank You.

 

[rascole]

I looked each exhaust hanger over twice while I was under the H3 today, yesterday so I'm at least a little more confident they all seem intact. But hey I'm humane and we are known to make mistakes lol.
The Diff mount also had my attention because I to felt like it was the definite place to spend some time but it seems tight and working correctly.
I've never changed the side bushings on the mount for the diff so that is a place to check.
Like wise the motor mounts are the same as when I bought Happy 10+ yrs. ago.
Great suggestions and I appreciate everyone's help and guidance. Thank You.

all good starting points, all are easy to fix.

 

[Happy Hummer]

Decided to order a new front drive shaft. It was just less hassel for the time being. I'll keep the old one for a winter time project for the basement. It's just a basic oem style. Not a fancy one like some of you guys are running. Lol!

 

[Happy Hummer]

Got the drive shaft replaced. Just came this weekend. Was able to install after biz day today. Seemed like a very nicely made shaft. Not at all the usual gaudy paint job and sloppy cr@p you usually see from over seas. All greased up and hope it works good for biz tomorrow.

Still need to check motor mounts and other bushings referenced early in postings.

 

[Happy Hummer]

Ok, so I've got a question?

I watched the video "how to place your t-case in Neutral" and I was able to do so...
BUT
Here is the weird thing. With the parking brake set. The wheels blocked. The transfer case in normal 4. I set the H3 transmission into neutral and pushed the hi4 and low4 for 10 seconds.
All is good its in (N) at transmission and transfer case. The weird thing I cant shift the transmission to (P) park because there is some movement still in the drive train. If I turn the H3 off and leave it in (N) and (N) for tans/trnfr it is fine.
The front of H3 was on wheel ramps when I was doing all this by the way. The H3 is running great and no drive issues as far as gears or positions on the transfer case settings.

Maybe I did not follow the directions thoroughly lol!

 

[Happy Hummer]

Still have to check motor mounts the fall.

 

[Jeepwalker]

My rig has had a 'clunk' about under floor pan since I bought it several yrs ago. Pretty much right when I take off from a stop sign during a light turn. I've checked all the usual suspects multiple times. I'm thinking it's the steering shaft 'popping' once the vehicle starts traveling. My theory (just a theory here) is the preload on the front wheels change from the braking process coming into a stop sign, and accelerating away. The pre-load change, changes the rotational torque on the intermediate shaft. And that causes the 'knee' of the intermediate shaft (where it bends) to go 'pop'. I keep meaning to put a go-pro in there to see if I can see it moving or 'popping' side to side while the noise happens, but I haven't done so.

The intermediate steering shaft has a funky angle to it and a u-joint at about the 'knee' of the multi-segment shaft. It seems to me that shaft would benefit if there was a bracket (and bearing) supporting it at the knee to the truck frame (keep it from flexing under steering torque). The noise on mine seemed to go away (or significantly minimized) after I initially replaced my rig's intermediate shaft with a new one, which leads me to think that possibly the cause of the nose. I was going to put a camera in there during driving and possibly fab up such a support bearing if it's 'moving' a little during normal DD steering. But so far I haven't.

But anyway, I'm not 100% sure if that's what's causing my truck's 'clunk' or if it's the same sound your truck has. That 'clunk' is not an uncommon complaint.

Have you check your door's hinge bushings? I test drove a H3 once that had a seriously worn lower driver's door bushing. Open your door 8" or so, and lift up on the bottom rear (below the door handle) with your hands. Lift up/down for movement. The door should be tight with no sloppy up/down movement.

If you have a go-pro maybe put it under your truck in a few different places and see if you can capture something banging around under there.

 

[Happy Hummer]

Yep, I made sure to put both lower and intermediate steering shafts in a few years ago. There still tight.
The doors are tight too. Good suggestions though.

 

[rascole]

Double check the trans mount. At a glance they may look tight because the trans is heavy enough to keep it snug against the cross member and the rubber bushing can breakdown over time. Tighten the nuts on the mount and the tranny.

 

[Happy Hummer]

You know im going to look into this. It is at least a plausible suggestion tightening the nuts.

 

[RamRod]

Have you checked the sway bar end links? Mine are worn out quiet bad and make a noticeable clunk in many different driving conditions.

Since I have the Rancho kit installed I was able to move the worn out ones to the rear and put the rears up front. Immediately the sound went away... well now I can't hear it all the way back there - the bushing is still worn out.

 

[Happy Hummer]

I will check those. They are all replacement ones that were done within the last 3-4 years. The front were greased Saturday but the backs were not looked at.

 

[H3Hummer]

I removed my front Sway bar since years now :wink: never regret and it flex much bette off road

 

[Happy Hummer]

Well as of Friday 10/22/2021 I'm not hearing the noise yet. Which of course is good. It is about 45 and poring rain Sunday 10/24/2021 so wont be able to check anything this week till maybe Wednesday, I'll definitely keep this thread alive and report back some more in the coming days. Thanks to all for suggestion so far.

 

[Exodus]

I've been plagued with a very similar issue the last few months,i found it when changing over to winter tires ,lift the rear axle off the ground and with it in gear\park give one wheel a good hard spin in both directions

discovered my t-case needs rebuilt

 

[Happy Hummer]

So, had a chance to check the sway bar links and the sway bar mounting point bushings. They are a o.k.... Greased up the rear links and there good to go. These are aftermarket ones installed a few years ago.
While under neath had a chance to just take in the sight and nothing else looks out of place at first glance.

 

[Happy Hummer]

I'll take the time to test your theory this weekend hopefully. I'm guessing you mean I should be in the H3 with the rear end lifted and supported? Then place the H3 in gear and accelerate the the vehicle. I'd think all four wheels would need to be in the air?

 

[H3Hummer]

Yep, indeed, all 4 in the air ! And safety first, hope you have good candles to put the H3 on.

 

[Happy Hummer]

Well the replacement front driveshaft I purchased is not so good lol! The old one is back in for now as the replacement one is vibrating pretty bad. Seems really well made but just zero balancing weights. Took a couple months to realize this. Haven't been driving as much with higher gas prices.

 

[H3Hummer]

:huh:what , which one did you buy? :whaa:

 

[Happy Hummer]

I purchased one from Amazon. The quality of the build is actually pretty good it just is not true with balancing.
For strictly off-road driving it would be fantastic but not so much at 55mph lol.