H3 Driveshaft clunk and knocking

[humvee]

Hey guys,

Installed this driveshaft 1k miles ago, now it spins quick and clunks when shifting in park.
While driving, I also hear and feel the clunk during shifting, crossmember bushing is solid though.
Getting knocking when accelerating at low RPMs, goes away when I'm up to speed. But when it is up to speed, something doesn't sound right, like a consistent resonating hum thats been slowly increasing with time, like a bearing.

Took it to a quick service, the guy checked diff and transfer case oil (by unscrewing the bolts and sticking his finger inside), says its all there?

Here's a video:
https://www.youtube.com/watch?v=ZurK0LNcYyM&feature=youtu.be

What do ya'll think?

 

[cgalpha08]

Hey guys,

Installed this driveshaft 1k miles ago, now it spins quick and clunks when shifting in park.
While driving, I also hear and feel the clunk during shifting, crossmember bushing is solid though.
Getting knocking when accelerating at low RPMs, goes away when I'm up to speed. But when it is up to speed, something doesn't sound right, like a consistent resonating hum thats been slowly increasing with time, like a bearing.

Took it to a quick service, the guy checked diff and transfer case oil (by unscrewing the bolts and sticking his finger inside), says its all there?

Here's a video:
https://www.youtube.com/watch?v=ZurK0LNcYyM&feature=youtu.be

What do ya'll think?

Is it a rebuilt shaft? or a new replacement? could be that the bearings at the transfer case end of it are bad somehow. IIRC the stock driveshaft has 6 balls in there under the rubber boot. Check it for leaks and make sure there is grease in there if you can. I know that is a common failure point on those driveshafts. Could also be a bad U joint

Now that i think about it the hum you are describing sounds like it could be a bad pinion bearing in the front diff. Try removing the front driveshaft and driving in 4hi lock, if you don't get the hum, then its safe to say you've narrowed it down to the front diff or driveshaft. East test to atleast try and pin point the issue.

 

[Bruces]

Pull the front prop shaft like suggested and see if cv joint or ujoint is bad. When my cv joint went out I thought for sure it was whole front end. Easy to replace.

If pinion bearing is going you will only hear hum when going fast and coast. Especially if coasting down hill at high speed like highway speeds. As soon as you give it gas it should less pronounced.

 

[woodwardsh3]

looks like a bad cv joint in the drive shaft at the transfer case end.

 

[08H3]

If it does end up being a prop shaft issue, get the Thorparts / Tatton setup. Problem solved for good.

 

[SuperBuickGuy]

I say this because I just dealt with this - the transfer case has an idler that can get loose and make the noises you're hearing. If you go through all other stuff and can't find it, do pull the case out and apart to check it - otherwise you'll be buying a new transfer case.

 

[rascole]

I agree with SBG. Seems like that is a lot of rotation in the drive shafts.

 

[humvee]

Guys you're a ton of help!

Its a new shaft, was last in stock when I got it tough. I'm always skeptical about the last items to go.
Hope its not the transfer case. Will delete the driveshaft and work my way through all of this after work tomorrow.


Thanks again guys

 

[4speedfunk]

Front diff! The driveshaft clearly rotates (along with the transfer case output), when you put it in and out of gear. I see ZERO slop in the CV, U-joint, or t-case action. That all looks perfectly normal and healthy.

However....what doesn't look normal is the amount of "lash" I'm seeing at the yoke on the front axle. Good Lord...there is at least 20 degrees of rotational slop at the yoke. Notice the front tire does not move but, the yoke has quite a bit of rotation. I work on these every day, and I can tell you...that front diff has a ton of lash, and its probably missing teeth to have that much slop. I would check the front diff fluid and magnet for a "tooth salad" (shavings). Could be a worn ring & pinion, pinion bearing, or spider gear issue. Whatever the case, it looks like its limited to something inside the front diff.

 

[USMC_TOP]

4speed, mine has the same amount of play either mine is junk as well or they are both fine...........


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[USMC_TOP]

4speed, mine has the same amount of play either mine is junk as well or they are both fine...........


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And my case is brand new


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[humvee]

SAS fever


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[Bruces]

If you need a new front prop shaft I would recommend OD. The have 1310 ujoints on both ends

 

[4speedfunk]

They’re all junk! Just in varying degrees.


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[humvee]

Thanks guys. Went under just now and took a look.
Its the boot where the drive shaft connects with the transfer case.
There probably was a leak, the steam wash last week must’ve removed all traces.

Would driving it for 15 days have an impact on the t-case? Until the part comes in.

Here’s the visual
https://youtu.be/tT5j-aixDPY


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[Bruces]

Cv joint on prop shaft is shot. This is the video I watched to learn to replace the cv. https://youtu.be/F5D-_2vrQNg

hard to say how long it will last but it is shot. I bought a replacement cv on eBay and it took about 30 minutes to replace.

 

[4speedfunk]

Glad it was something simple (and cheap). That’s no environment for a booted CV. If it doesn’t hold up...swap to a real driveshaft with solid u-joints.


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[Bruces]

Upgraded prop shaft

This the one I have now http://www.outfitterdesign.com/h3-front-driveshaft.html

 

[SuperBuickGuy]

Thanks guys. Went under just now and took a look.
Its the boot where the drive shaft connects with the transfer case.
There probably was a leak, the steam wash last week must’ve removed all traces.

Would driving it for 15 days have an impact on the t-case? Until the part comes in.

Here’s the visual
https://youtu.be/tT5j-aixDPY


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that's not a boot problem, that's a CV problem.... If I had to, I'd drive it as slowly as possible - the problem is that vibration will do all sorts of bad things to your transfer case. Pull the front driveshaft and drive in 4 high lock if you need to drive it....

 

[humvee]

Thanks, thats what I’ll do first thing tomorrow.
Afraid won’t be able to get around to a proper fix before 10 days.

Forgot OD had those, would’ve bought that instead of the one I got. Cost me $700 from the dealership here.


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[humvee]

what doesn't look normal is the amount of "lash" I'm seeing at the yoke on the front axle. Good Lord...there is at least 20 degrees of rotational slop at the yoke.

Never ruled out front diff problems. Just removed the driveshaft, the noise the cv joint was making is gone of course, but the overall drop in noise is something else, the commotion and rumble that predated the shaft issues is now completely gone.

Does this mean my problems were limited to the shaft?

Or could it be that the front diff simply runs louder when connected to the transfer case?

I can get used to the serenity.



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[4speedfunk]

Serenity...haha. That’s a good description. If we only had a 2Hi mode on the t-case to shut all that off.
Without question things are much quieter without a front driveshaft. The front diff is still turning but it’s being driven by the front wheels on the coast side of the teeth. The pinion bearing does not see near the thrust load that it does when being driven by the shaft. This can magically eliminate noise & vibes. And like you say...it’s no longer directly connected to the power train.
If you haven’t done so yet, it might be worth popping the cover and having a good look inside. At the very least, drain it and check the magnet for chunks. With the shaft out...grab the yoke with your hand and see if you can feel any excessive lash, wobble, or looseness. Almost every 80k mile H3 that passes thru here has zero preload on the pinion bearing. Some run forever like that but most need new pinion bearings & races to get rid of the growling and/or whining. My policy on the AAM-7 is...”If ain’t broke, don’t fix it”.

Also there could be some wear on the front output of the t-case, from driving around with a smoked front driveshaft, depending on how long you drove it like that. The t-case is pretty durable but you can check it the same way as the front diff. It’s normal to have gobs of rotational lash at the t-case output flange (from chain slop) but there should not be any wobble or side-to-side slop.