Rear clunking noise when making left turns

[Capote]

I wasn't 100% whether or not to post this under the Brakes & Suspension section or in Drivetrain. Mods, feel free to put this in what section you feel is appropriate please

@HARDTRAILZ @Mooseman

I'd say for about a month I've had a single, distinguishable clunk noise when making left hand turns and only left hand turns from a stop or from an incomplete stop followed by a left turn. This noise sounds like it is coming from the rear passenger side, but i'm only 80% sure on that. This clunking noise does not occur at all when going over bumps you'd encounter daily on the road or even large speed bumps, which I go over daily as well. I was pretty sure this wasn't an end link clunking issue as I had just replaced all four 3 weeks ago. So I went under the rear of my truck tonight grabbing on everything that could move to see if something is loose. I checked the new end links, sway bar, panhard bar, bottom of shocks near bushings, and everything is solid and not moving by hand. I even checked all the paint marked nuts on all the end links and everything is still lined up.

The only worn out bushing/suspension components on my truck that I know 100% need replacement are the front sway bar bushings.

Now I've been looking on the old site and on ORTB about rear clunks being heard from the rear during a left turn. Apparently there can be an issue with the rear axles, more-so with the ones that have a G80 locker, just like the 8" one I have that I swapped over from a Rainier late last year. Most of the cases had axle shafts that had too much horizontal play when pulled and pushed on. Others, when taking the rear diff cover off, discovered teeth had broken off and were sitting down in the gear oil when it was drained. Another issue I read dealt with components worn out within the diff like the C-Clips or clutch packs worn down? I visually checked my rear axle and I see no signs of there being a leak, so i'm too worried there might be a lubrication issue in there.

What I wasn't able to do tonight is jack up the rear end and pull the wheels forward and back to see if there's movement. I am also gonna see if there's any play with the u-joint. Even though every time I've had my driveshaft out I didn't have any play with that. Anything else I am not thinking of here guys that could be making this clunk? I also gonna consider having my tune edited to lower the shift pressure a bit, when I go wide open throttle from a dig or low speed my truck shifts hard as hell, making the tires chirp (not the belt) into 2nd.

 

[Mounce]

Yeah, was gonna recommend a push/pull test on the wheels after you brought up diff issues but I think you know that's the next thing to check if nothing else comes up.

 

[Capote]

Yeah, was gonna recommend a push/pull test on the wheels after you brought up diff issues but I think you know that's the next thing to check if nothing else comes up.

I understand that some play is normal from what I've read, but I didn't get any measurement as to how much is tolerable or "normal". I won't know until I can actually do this test and see if that's even a possibility. Right now i'm sifting through @Mooseman 's greatly appreciated Service Manuals I downloaded to check up on this.

 

[Mounce]

Right, you'll anyways have a little in/out play but who knows what's acceptable. If you're getting more than a few mm I'd pull the cover and check it out to be safe.

 

[Capote]

Right, you'll anyways have a little in/out play but who knows what's acceptable. If you're getting more than a few mm I'd pull the cover and check it out to be safe.

I planned on pulling the cover anyway to drain the fluid, see what kind of condition everything is in, and how the fluid looks. And since I am having this noise it'd make me feel a helluva lot better if I saw nothing broken.
Did see one video though where a guy had a lot of play on both wheels. He opened up the rear diff, had no visual issues. Yet he still had to have his rear axle rebuilt apparently. Guess he had someone more knowledgable check it out and that was the answer.

 

[Capote]

@Mounce Found out that the wheel play shouldn't be more than 1/2" back and forth. Found that info on TBSSowners.


Looking through the 02-05 Service Manual's under the Limited Slip/Locker and the Driveaxle section, I am only seeing a few reasons as to why a Locker or the Rear Axle would make noise during a turn under normal operation:

Locker:​

Axle:​

 

[AWD V8]

All C-clip rear ends will have horizontal play. I've found that most have about 3/16" at most. I would not consider any more to be acceptable. Even with only 3/16" if you grab the wheel and push/pull it will clunk loudly. More movement would indicate a worn c-clip groove on the axle.

 

[Capote]

All C-clip rear ends will have horizontal play. I've found that most have about 3/16" at most. I would not consider any more to be acceptable. Even with only 3/16" if you grab the wheel and push/pull it will clunk loudly. More movement would indicate a worn c-clip groove on the axle.

I'll be sure to pay close attention to how much play there is when I get a chance to get the rear end off the ground.

Found this on TBSSowners, it mentions the C-clips:

"As the clutches wear, side gear shim wears, pinion shaft to carrier housing wears and carrier case hole wears then this dimension increases. Possibly the pinion shaft wearing also. Believe the c clips only come in two thicknesses .150" and .155". So buy adding the thicker clip will tale up 0.005 on each side. If the pinion shaft diameter has not been ground down by the axles (mine are not) and the pinon shaft is good then the distance if done originally correct is caused by the clutch pack wear, and back face of side gear wear and side gear shim wear. It allows the side gear to move closer to the carrier wall (away from the pinion gears) and allowing the axle end play to increase. So theoretically just putting in a thicker c clip would reduce this play.

Don't know what the max is before some other issues arrise. If it is just caused by clutch pack wear than you are talking about the total thickness of the wear portions of the clutch plates. You will have lost the posi of the rear end by then.

Ours is a GM semi floater the carrier is preloaded via a shim on the drivers side and a carrier adjustment nut on the passenger side (circular nut with holes). This sets the carrier bearing preload and ring gear alignment depth to the pinion gear. If this gets loose then you will see increased ring to pinon backlash and axle end play increase.

A lot to figure out.

Best thing to do is remove the cover and find out what is going on.

Currently mine is at 0.030 (~1/32). Removed rear cover and found out some other wear issues. Got wear at pinion gears to pinion shaft. Pretty significant for 69K miles. Slid the pinion shaft from the gear and there was some wear on it, but looks like most of it is the pinion gear bore. Ring and pinon backlash good though. Trying to decide whether to put in a complete new Eaton Posi or rebuild this one."

 

[Capote]

So this isn't a noise isolated to turning, as I previously thought. Turns out I get this single clunk noise upon moderately fast/sudden braking from a slow speed or sudden acceleration from a stop. I can't figure out what this is. Today it was very frequent.
-End links are new
-Everything with the brakes it torqued tight
-Rear sway bar doesn't appear to be hitting rear diff cover
-Front sway bar does need new bushings, but the noise is coming from the rear

Besides maybe putting grease on the slip yoke where it joins with the tail-housing or checking the diff yoke for play, I'm out if ideas. Any specific type grease needed for the slip yolk to tail housing area?

 

[HARDTRAILZ]

I just used a tub of red grease i had for years, nothing special.

 

[Capote]

I just used a tub of red grease i had for years, nothing special.

Cool, I've got some kind of all-purpose automotive grease I have unused from a crap grease gun I have.

 

[Mooseman]

I get this single clunk noise upon moderately fast/sudden braking from a slow speed or sudden acceleration from a stop

I have the EXACT same problem with my 'new' 07. Come to a stop and "thump". Not a noise, just feel it in my seat. Seems to be more prevalent when I come to a stop on a slight uphill incline. It's like if the brakes are loose and the backwards countershock is making this thump. And it just passed a safety. I'm thinking it's one if the bushings in a rear suspension arm or a u-joint.

 

[Capote]

I have the EXACT same problem with my 'new' 07. Come to a stop and "thump". Not a noise, just feel it in my seat. Seems to be more prevalent when I come to a stop on a slight uphill incline. It's like if the brakes are loose and the backwards countershock is making this thump. And it just passed a safety. I'm thinking it's one if the bushings in a rear suspension arm or a u-joint.

Everytime I hear the clunk it makes me cringe, just sounds so bad. Truck drives like a dream though. Seems to be quite a prevalent thing, upon my research digging around here and on the other forums. Some never found a fix, while others replaced their rear diff fluid or greased a driveshaft component to resolve the issue. I'll start off first by greasing the yoke and seeing if the U-joint is reaching it's end of serviceability. The Rainier I got the rear axle from was a rust bucket underneath. If some good ole' lube doesn't fix it, i'll drain & replace the diff fluid.

@Mooseman If it's a bad bushing on a trailing arm, that's a good excuse for an upgrade to Spohn or BMR ones

 

[xavierny25]

I'm thinking it's one if the bushings in a rear suspension arm or a u-joint.

I've got that same thing going on in the voy and I just replaced both rear bearing and seals. Everything else in the rear of my voy is practically new except the trailing arm bushings and ujoints.

 

[Mooseman]

The weird part is that my '02 with 300k km never did that and this one with 89k km does. Very strange.

 

[Tiggerr]

I'd say rear control arm or panhard bar bushing sounds most likely....possibly a shock mount/bushing...

 

[Capote]

I don't want to remake a new thread due to this to clutter up things, but:
This clunk has nothing to do with being isolated to making turns since i've last posted. This is definitely something related to deceleration and acceleration. For a month now I noticed that this clunk would sometimes be in the back, then be in the front somewhere below the center console. So this makes me believe this is an issue with the u-joints, yoke, or slip yoke. I'm changing my oil this weekend, so while the truck is up, I'm going to remove and inspect things. I know the u-joint should turn smoothly with some resistance and not be sloppy or feel crusty when moving (never has all the times I've installed it). Are there any other signs of a bad u-joint besides those? I am not sure if there's any natural play involved or not with the yoke on the rear diff, I need insight when it comes to that. I'll also be greasing the slip yolk as well. Anything else I should look out for with the rear diff/drive shaft?

 

[Tiggerr]

I don't want to remake a new thread due to this to clutter up things, but:
This clunk has nothing to do with being isolated to making turns since i've last posted. This is definitely something related to deceleration and acceleration. For a month now I noticed that this clunk would sometimes be in the back, then be in the front somewhere below the center console. So this makes me believe this is an issue with the u-joints, yoke, or slip yoke. I'm changing my oil this weekend, so while the truck is up, I'm going to remove and inspect things. I know the u-joint should turn smoothly with some resistance and not be sloppy or feel crusty when moving (never has all the times I've installed it). Are there any other signs of a bad u-joint besides those? I am not sure if there's any natural play involved or not with the yoke on the rear diff, I need insight when it comes to that. I'll also be greasing the slip yolk as well. Anything else I should look out for with the rear diff/drive shaft?

I still say while your under there check all your rear bushings...control arm, panhard bar...

It could be the whole rear end clunking around if a bushing took a vacation..or even a busted arm.. they're just cheap mild steel tubing...

I'd double check your shock mounts too... anything back there can move on accelerating/decelerating if it's not buttoned down....

Another thought I just had was make sure your spare is up tight to the body...that'd clunk a bit on accelerating or decelerating if it was loose...

 

[Capote]

I still say while your under there check all your rear bushings...control arm, panhard bar...

It could be the whole rear end clunking around if a bushing took a vacation..or even a busted arm.. they're just cheap mild steel tubing...

I'd double check your shock mounts too... anything back there can move on accelerating/decelerating if it's not buttoned down....

Another thought I just had was make sure your spare is up tight to the body...that'd clunk a bit on accelerating or decelerating if it was loose...

Shocks are only 3 or 4yrs old? They're good, checked those already. My trailing arms are also good, those are BMR aftermarket beefed up ones with poly-bushings that I recently re-greased. As far as a spare tire, I have neither that or the spare tire carrier. Those are one of the first things I ever removed from my truck.
This clunk will either be in the front when it occurs or the back. I'm gonna check everything over again anyway, then for play with the yoke's and etc. tomorrow.

 

[Tiggerr]

Check your trans mount too..
and whatever mounts there are for TC if it has any of its own...

Got to be something loose somewhere...

Other than the loose nut behind the wheel lol

 

[Capote]

Check your trans mount too..
and whatever mounts there are for TC if it has any of its own...

Got to be something loose somewhere...

Other than the loose nut behind the wheel lol

It's driving me nuts because it doesn't always happen and I usually can't make it occur if i'm trying. Torque Converter is on my list of things to check. I had a bad experience with that already once before.

 

[mrrsm]

This is going to sound like a crazy idea... but apparently... stuffing a New Black Hard Rubber Hand Ball deep inside of the end of the Rear Drive Shaft Splined Hollow Tube innards, in addition to using copious amounts of the AC-Delco flavor of a cup grease, this can act as a "Pneumatic Buffer" in there to take up any free space and still flexibly absorb and cushion the in and out motions of the Rear Drive Shaft Spline and permanently eliminate the Infamous GM Clunking Problems.

I suspect you would notice a bit of difficulty in getting the tail end U Joints and cups back in place during the re-installation of the drive shaft into the rear differential yoke and using a pry bar to overcome the 'squeezing hand ball' would be necessary. What the Hell... Right? It does not seem like it would be harmful in any way... but some may suggest otherwise.

 

[Capote]

This is going to sound like a crazy idea... but apparently... stuffing a New Black Hard Rubber Hand Ball deep inside of the end of the Transmission Hollow core splined innards, in addition to using the AC-Delco flavor of a cup grease, can act as a Pneumatic Buffer to absorb and cushion the in and out motions of the Rear Drive Shaft Spline and eliminate the clunking problems permanently.

I suspect you would notice a bit of difficulty in getting the tail end U Joints and cups back in place during the re-installation of the drive shaft into the rear differential yoke and using a pry bar to overcome the 'squeezing hand ball' would be necessary. What the Hell... Right? It does not seem like it would be harmful in any way... but some may suggest otherwise.

Interesting, I've never heard of anyone doing that before. In theory it makes sense quite a lot, but to be honest I don't really want to be stuffing anything in that small hollow section you're mentioning. I just want to identify the location of the clunk in-case it's something in need of replacement before it's too late, or something that needs to be tightened.
I'll be checking TC bolts, yoke straps, u-joints, diff. yoke, slip yoke, bushings, shocks, and damage to the driveshaft itself.

 

[Mooseman]

 

[Capote]

Didn't get the truck jacked up today, figured i'd wait for tomorrow because I got to go get an oil filter for the oil change. Didn't want to lug that 100lb beast of a jack two days in a row down to the parking lot. But I may of discovered a possible cause for the clunking. I noticed today that my front end-links move way too easily (which would probably mean the rears as well). They took little effort to rotate side to side vs. when I first installed them a month or so ago. I'm thinking these Ebay end-links may already be shot, they just don't happen to make any clunking noise over bumps, so i'm not 100% if this is the cause of the noise until I can take a look at everything I had on my list to check tomorrow.

 

[Mooseman]

Rotating is OK. You have to use a long prybar and pry up and down on the sway bar.

 

[Capote]

Rotating is OK. You have to use a long prybar and pry up and down on the sway bar.

Even if it's this easy to move them? Damn, I totally forgot about using one to test them . If I hadn't of already showered i'd go quickly do-so.

 

[Mooseman]

Tomorrow is another day

 

[HARDTRAILZ]

When my trans mount was bad you felt it most going into gear. Could see the motor shift.

The slip yoke definitely had a clunk that had me puzzled years back. Grease it anyways.

 

[Capote]

When my trans mount was bad you felt it most going into gear. Could see the motor shift.

The slip yoke definitely had a clunk that had me puzzled years back. Grease it anyways.

The trans mount was one thing I thought it could of been. I have payed close attention to see if it does this from 1-2 or 2-1 shifting and it isn't consistent with that.

Grease is something i'll definitely do for sure.

 

[HARDTRAILZ]

My between gears was no noise or anything to notice with trans mount. It was the hit going frm N to r or D or P to R. 1-2-3-4 was all smooth