Is it the Crossmember?!?!?!

[hockeymanam]

So in the last couple month I have a nice sound clunk from the drivetrain when I'm off the gas and quickly get back on it. Ex: going down the hwy and letting off for slowing traffic and then getting back on it, I will get a very solid clunk from right under me it feels like. Also when i put it in park i get a lot more roll fwd or backward the usual. I feel that its related but what do y'all think?

 

[cgalpha08]

I have the same thing, I do not think its the crossmember but rather the rear driveshaft slipping forwards and backwards where it connects to the t-case. I know this happens with other gm trucks, not 100% if it happens in the H3 or not. It could be even worse, some sort of slippage in the diff or trans

 

[IISPEEDYII]

Yeah I have this too! I hope it's not the Trans though. A large clunk after coasting slightly and then putting on the gas again.


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[3Hummers]

Could be a U-joint, body mount...a number of things.

 

[USMC_TOP]

Welcome to AWD........

 

[4speedfunk]

Same thing. Check your t-case fluid. Mine was doing all sorts of crazy stuff. Eventually It got so violent I replaced the whole case with a new one.

 

[AlaskaDan]

Mine does the same. I was thinking its the transfer case chain due to stretching. Is not so bad atncold temps but gets worse at high steps like hiway driving. Well check my transfer fluid.

 

[AlaskaDan]

4speed where'd you get your tcase?

 

[hockeymanam]

Well i will check my fluid but it sounds more mechanical or something loose. I know the crossmember is something that is weak on the 3 and I didn't know what that feels like if it goes bad. Did buying a new t-case solve the problem completely? cause if it has to do with slack in the driveshaft wouldn't the prob just reappear? If you can't tell drivetrain is not my speciality

 

[deserth3]

I assume this is on a 3.
Could be the cv joint on the front drive shaft.

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[AlaskaDan]

Not for me. I had the wife shift through the gears (with tires chalked of course) while I crawled around under. Nothing seemed lose and sound to be coming from tcase

 

[digglesworth]

It's easier to start small and work your way up. A t-case is gonna run you $12-1500... Crossmember bushing/bushings (depending on which one you go with) will run you a couple hundred. It sucks replacing something and it not fix the problem but at least you get the piece of mind of another part that's been "freshened up".... The bushing fix is a worthwhile upgrade whether it's the problem here or not. Win, win.... I'd start with the bushings. Then u-joints. Then cv on the prop shaft.... Maybe a complete drain and fill of the t-case and diffs while you're at it. Just my opinion.

 

[Zach]

It's easier to start small and work your way up. A t-case is gonna run you $12-1500... Crossmember bushing/bushings (depending on which one you go with) will run you a couple hundred. It sucks replacing something and it not fix the problem but at least you get the piece of mind of another part that's been "freshened up".... The bushing fix is a worthwhile upgrade whether it's the problem here or not. Win, win.... I'd start with the bushings. Then u-joints. Then cv on the prop shaft.... Maybe a complete drain and fill of the t-case and diffs while you're at it. Just my opinion.

New tcases are not in the $1200 range anymore. A few months ago the cost jumped to same as a non 4.10. You bought yours just in time. The second one I ordered for you was the new price

 

[4speedfunk]

Yup. I got mine from my local GM dealer for $1150. I checked the other day and it's up to $1600.

Frankly...at that price it's worth looking into some other case. Because I have lockouts on the front hubs, a 2wd mode is a real possibility. For those of u with the stock ifs...your stuck with the 4494.

 

[TR1-H3X]

Hockey...did you ever get this figured out? I ask as I have a sorta sim issue- mine ONLY happens at 10ish mph..if I lift / slow and get back on the gas I get a dt thunk. If I let it coast longer, no thunk. If I lift n gas a cpl/few mph above or below 10, no thunk. I've been told by a bunch that its just GM DT slop, and it may be, but my Suburban didnt do this, even at 250k, none of my other GM trucks did it... Its not a huge deal but it drives me crazy and it hasnt gotten any worse over the year plus I've had it, but I'd rather take care of it if its a identifiable fixable issue.

TY to any with input
Happy New Year

 

[LagunaH1]

My 08 H3 Alpha had a very similar thing going on. The H3's do have some amount of "lash" (free play) in the drive line and that's normal. I think more diagnosis is required to determine if what you are hearing is just the normal sound of the drive line loading up after having been un-loaded, or if something else is going on.

A visual inspection can probably tell you if the front cross member diff carrier bushing is ready for replacement.

 

[hockeymanam]

Actually the other week I crawled under there and started tugging on the driveshafts and had someone change gears and roll while I was under it.. I could not see or force the DS to move any extra.. I feel as its is some where in the rear diff.. Only say that because thats where the clunk comes from... It has not gotten worse in the last two years so it may be normal (ish)... But I will be replacing the crossmember in the future cause i did see that my bushing was to hell. So maybe that will fix it if not then I give up!!