H3 Transfer Case People - Need Advice

[jimmy p]

2006 Hummer H3 4:1 Adventure Case, Ls2 swap and SAS. Tcase was used when I pulled it, had about 200k miles on it when I swapped it in 2 years/1000 miles ago. Before I installed it I replaced the shift fork, inspected everything internally and added new fluid, been working fine for a couple years offroad. The last two times at a local offroad park I have been getting a thump under the passenger side floorboard when doing hillclimbs. Originally thought it was the exhaust bouncing but I have since almost solidly mounted the exhaust to eliminate that as a possibility. I am also pretty certain it isnt suspension related now as I have fully inspected everything for contact, shocks are not bottoming out etc. I am pretty sure it only happens when in 4 hi lock and going uphill, or turning in mud/ruts and accelerating. So far I have never replicated it on the street, no noises in 4HI standard, no noises on deceleration. I have drained the fluid, it is dark but clean, no metal or chunks. I am fairly certain the noise is coming from the t case but wanted to see if there is anything else I can do to verify it. Ideas? Does a stretched chain skip in 4HI lock and not 4HI street?

I am probably going to open it back up, at a minimum replace the chain and look for any worn teeth again etc.
I see the borg warner chain is only about $80. Is it worth doing a full rebuild while I have it apart this time with bearings and seals? What rebuild kit is recommended? Anything else I need to do while I have it apart?

 

[06 H3]

Based off of memory chain stretch would have to be pretty damn bad for stretch in 4 hi unlocked. Reason being is that it’s got an “open diff” when in 4 hi unlocked so instead of the chain skipping the open diff absorbs the resistance.

In 4 hi lock there is so slack via “open diff” so the chain skips

 

[jimmy p]

Here is the bearing and seal kit I am looking at is anyone has any experience with it.

More Information for USA STANDARD GEAR ZTBK4493

 

[08H3]

Its also possible the snubber came loose and it's floating around in there and getting caught in the chain. Kind of a chicken or the egg thing though. Did the chain stretch, whip against the snubber and break it loose, or did the snubber come loose, end up in the wrong place and stretch the chain? Either way, that happened to me several years ago and the symptoms are exactly as you described. First noticed the thump while offroading, and eventually got the same thump on the street under moderate throttle.

 

[rascole]

I had a similar issue only in 4 Low, the gears were out of sync when reassembled. Use a GoPro type camera with a magnetic mount to video several areas around the TC. Has worked for my for many issues. Make sure the planetary gears are lined up correctly.

 

[atvspeed4]

I have had that happen with a stretched chain as well. If the truck is on pavement with pretty equal torque there is nowhere for the differential to distribute torque and chain skips. I would just replace chain an check planetary alignment as suggested above.

 

[jimmy p]

Thanks guys, new chain is on the way. Will post up what I find when I get it opened up.

 

[jimmy p]

Case is apart. No evidence of chain skipping on the sprockets or coming in contact with the case wall. No debris, filter is clean, slight smear of fine metal on the magnet only. New chain and old chain appear the same on the bench, but I was able to measure a bit of deflection improvement when the new one was installed. Is that consistent with what others saw with the noise and chain replacement? I was hoping to find something more obvious to explain the noise before I seal it back up and wrestle it back under to reinstall it.

 

[jimmy p]

Old chain

 

[jimmy p]

New chain

 

[Jeepwalker]

Am I reading that right? Old chain has less 'stretch' than the new chain?
Or are the pictures mis-labled...

 

[08H3]

I think the pics are correct. About .125" - .1875" less with the new chain. I don't think that's enough stretch to cause it to skip though. That sucks if you spent the money and time on the project if that wasn't the issue. While you have it opened up, 4speed modified mine and changed out the bolts that hold the snubber to a stud and locknut. I think that's a worth mod while you have it apart.

 

[rascole]

Remember to assemble it exactly as the procedure says. If the marks do not line up you will get the pop like I did in low range.

 

[jimmy p]

While you have it opened up, 4speed modified mine and changed out the bolts that hold the snubber to a stud and locknut. I think that's a worth mod while you have it apart.

I found 4speeds old post but no snubber in the 06 cases.

 

[jimmy p]

Remember to assemble it exactly as the procedure says. If the marks do not line up you will get the pop like I did in low range.

Thanks, I am still assuming I assembled it correctly the first time since this issue was not present until recently. Will be cautious again as it goes back together and do the function checks to looks for binding.

 

[jimmy p]

Back together last night with a new chain and fluid and gave it another try at the local park today. I also removed the pass slide slider thinking that was contacting the body on bumps. Unfortunately the clunk still exists. Ujoints only have a few miles on them, no apparent contact between exhaust and body, or suspension components. I'm wondering if it is rear axle wrap or some kind of binding in the driveline when flexing or weight shifting backward on uphill climbs.

 

[alrock]

I've had a front end clunk with bumps and drops for years and I've replaced nearly all, or all, of the front end suspension and steering components (many of them a couple of times) and I can't get rid of it. Also replaced every motor, trans and diff mount. And exhaust.

Other common clunks, and hard to see sometimes, are when the upper or lower control arm bushings are worn, or the rear leaf spring bushings are worn. What about the bolt-in crossmembers - are they tight?

 

[rascole]

Does the noise happen in all 3 TC modes? Is it speed or RPM related? Don't rely on visual inspection of bushings. Put the front frame on stands, let the suspension hang, move suspension around looking for loose parts. Diff and outer axle bushings are the usual suspects BUT, any rubber part can be the problem.

 

[jimmy p]

Between the engine swap and SAS/SOA most of everything under the truck has been replaced or serviced in the past 3000 miles so I am really going to be surprised if it is a worn rubber component but maybe if something is misaligned it could wear quickly. X member and trans mount was just inspected and torqued when the tcase came out. The rear leaf shackle mounts might still be original so I am going to inspect and probably swap those out next. I will also try getting the wheels off the ground and looking for suspension wear as suggested.

So far I have only had it happen in 4hi lock which is why I suspected the tcase. It only occurs when on the throttle and the suspension is going over a bump, almost always up hill. Never happens off throttle when I try to max out the suspension. It did happen once while doing a hard donut style turn in snow today in 4hilock, but would not happen doing the same thing in 4hi street.

Thanks for the ideas, I will update if I find anything.