05 Flame Red TJ Build

[DrDmoney]

I know the DS went to Adam's but maybe it's worth looking at the double carbon joint since they didn't replace it.

This is a good point @Alex01 is making, they may have fixed the obvious and overlooked the DC. Even if they spun it they might have missed it because it only happens under load.

Those races appear to have wear and maybe some fragments rolled into them. I'd put all new bearings and races in while its apart.
What is the history of the axle again?

Agreed, unless that axle had 100k on it with no oil change and super fine stripper glitter in it, I would be concerned.

 

[JMT]

I am not at all mechanical, so this may be a daft idea. If you think it may be a driveshaft issue would it be possible to swap the driveshaft with the one in the Twin’s TJ and see if you get the noise then?

That’s a good idea, but their shaft is not double cardan. I asked people in the largest Jeep club up here on FB if anyone had a DC shaft they would let me swap just to test. All I got was people saying fix your pinion angle. Yeah ya twit, I already tried that.

 

[DrDmoney]

That’s a good idea, but their shaft is not double cardan. I asked people in the largest Jeep club up here on FB if anyone had a DC shaft they would let me swap just to test. All I got was people saying fix your pinion angle. Yeah ya twit, I already tried that.

Didn't I send you a shaft with the 4:1?

 

[JMT]

This post on Cherokee Forum reads like it’s right out of my playbook.

https://www.cherokeeforum.com/f2/noise-coming-rear-drive-shaft-sye-261062/#post3664053
This one on a Bronco forum reads very similar and the video slow mo is just like mine.

https://www.fullsizebronco.com/threads/bad-double-cardan-joint-or-broken-pinion.429953/

 

[JMT]

Didn't I send you a shaft with the 4:1?

Yes, but I think it’s a 1330 and mine is 19” long and yours is 16’ish (I’d have to go measure to be exact).

I’ll go check again, seems like I already checked sometime in the last month. Memory getting blurry.

 

[JMT]

Those races appear to have wear and maybe some fragments rolled into them. I'd put all new bearings and races in while its apart.
What is the history of the axle again?

This may be, but is it really going to cause a clunk you can hear at 30 yards? I’ll take a video of the races. The bearings look and turn fine.

And would a imperfect race cause rotational clunking with speed increasing?

 

[Alex01]

This may be, but is it really going to cause a clunk you can hear at 30 yards? I’ll take a video of the races. The bearings look and turn fine.

And would a imperfect race cause rotational clunking with speed increasing?

That's why I really think the DC joint is worth rebuilding.

If you dont want to take it on maybe have TW fully rebuild and shorten @DrDmoney's? Assuming the boys get a ss sye in the future it isn't a total loss and you'd have a spare.

 

[DrDmoney]

would a imperfect race cause rotational clunking with speed increasing?

not likely

That's why I really think thr DC joint is worth rebuilding.

If you dont want to take it on maybe have TW fully rebuild and shorten @DrDmoney's? Assuming the boys get a ss sye in the future it isn't a total loss and you'd have a spare.

This^

 

[Farmergreg]

This may be, but is it really going to cause a clunk you can hear at 30 yards? I’ll take a video of the races. The bearings look and turn fine.

And would a imperfect race cause rotational clunking with speed increasing?

Obviouly not the root cause, but like the TC bearing you replaced, I'd replace those races.

 

[JMT]

Adams just called me back after an earlier discussion. He said he thinks that a TCase drop may help diagnose the problem. I told him my angles were 22.5* and asked what the angle limitations were in the shaft and he said 23-26*, but it would be worth it to try and see. Of course, I have the Savvy MUA, so the crossmember would have to go away to lower the case. I could swap out springs for something shorter, otherwise I don’t know a way to test this. The other thing is that the driveshaft angles have been this or close to it for awhile now, but this problem hasn’t.

EDIT: I could throw a lot of weight in the back and see if I could change the operating angles enough to eliminate the problem. I've got 2 35's on rims, 1 33 with a rim, and a spare for the boys TJ I could throw back there. That's got to be 250lbs.

 

[Alex01]

Adams just called me back after an earlier discussion. He said he thinks that a TCase drop may help diagnose the problem. I told him my angles were 22.5* and asked what the angle limitations were in the shaft and he said 23-26*, but it would be worth it to try and see. Of course, I have the Savvy MUA, so the crossmember would have to go away to lower the case. I could swap out springs for something shorter, otherwise I don’t know a way to test this. The other thing is that the driveshaft angles have been this or close to it for awhile now, but this problem hasn’t.

If it fixes the problem what's his next step? Seems like a waste given it was working fine prior.

 

[JMT]

@DrDmoney called and said it had slipped his mind but he had this same sound about 5 years ago for a couple of hours and a buddy took the shaft and fixed it. It was so short lived he had forgotten. Re-building the shaft fixed it.

He also suggested I take the driveshaft he sent me with the Tera-Low that was hooked up to a Dana 44. It's shorter due to the traditional Adams SYE, but I could take the front half of his DC and the rear half of mine as long as the splines line up. I could at least check it. I'd mark everything so I can return the shafts to the right splines afterward. I'm going to look at that later today if I can finish my work, or tomorrow since it's my day off.

 

[JMT]

If it fixes the problem what's his next step? Seems like a waste given it was working fine prior.

Agree. It's been working fine since I put these coil springs on before Moab. I've had the shaft as high as 23.5 and as low as 21.5* with no change. It used to work fine at either of those angles.

I'm going to start by checking a few more things in the diff, and if I don't find anything, put everything back together and get @DrDmoney shaft down and start experimenting.

 

[Alex01]

@DrDmoney called and said it had slipped his mind but he had this same sound about 5 years ago for a couple of hours and a buddy took the shaft and fixed it. It was so short lived he had forgotten. Re-building the shaft fixed it.

He also suggested I take the driveshaft he sent me with the Tera-Low that was hooked up to a Dana 44. It's shorter due to the traditional Adams SYE, but I could take the front half of his DC and the rear half of mine as long as the splines line up. I could at least check it. I'd mark everything so I can return the shafts to the right splines afterward. I'm going to look at that later today if I can finish my work, or tomorrow since it's my day off.

Well you have a 50/50 @DrDmoney / @JMT TC so it's only only fitting the DS would be the same

 

[JMT]

Some more info for those who are interested.

I haven't really messed with the rear pinion much this year. It was the front driveshaft that I messed with quite a bit after Moab. This was because I was getting harmonic vibes with the 4" RockJock coils. I was also still on 33's. I drove it to Moab like that. 1,000 miles of vibrating. I removed the front shaft for the drive home. After I got home I messed with it to try to regain some caster, moved the axle slightly forward, and got to 4.8*. That's where I left it. I checked the rear shaft and pinion angles at that time and made a slight adjustment. That had to be back in May or June. This problem now didn't come on till mid-November. The 35's actually helped with the harmonic vibes. They don't come on till around 70mph now, whereas before it was about 64. That has to do with the 456 gears. If I went up to 488 or 513 the harmonics would come on sooner and I'd be forced into hubs. They're still in the $1360 range due to the Covid supply-demand economics explicated by Adam Smith.

 

[bobthetj03]

I doubt it's the pinion bearings, or any of the rear diff bearings for that matter. I don't have as much faith in Adams DS's as most, so I think your pointing in the right direction with the double cardan joint.

If you go back into my thread a bit, you'll see what my outer pinion bearing looked like, and when I did the first re-gear, my carrier bearings were trashed. Only indication I had was a howling noise. No clunking like you're experiencing.

 

[JMT]

I doubt it's the pinion bearings, or any of the rear diff bearings for that matter. I don't have as much faith in Adams DS's as most, so I think your pointing in the right direction with the double cardan joint.

If you go back into my thread a bit, you'll see what my outer pinion bearing looked like, and when I did the first re-gear, my carrier bearings were trashed. Only indication I had was a howling noise. No clunking like you're experiencing.

I wanted a Tom Wood DS from the beginning, but this one came up for $75, which was hard to pass up.

I will go take a look at your outer pinion bearing.

All I'm going to do in the diff now is reach to the frontside (hidden side) of the pinion teeth and make sure I've felt every tooth on that edge just to make sure I'm not missing something. I'll need to replace my e-locker connector on both ends and make sure I add a little wire so it doesn't pull lose on articulation.

Thanks to all of you for reading...and helping..andputting up with my shenanigans.

@UKTJ. I am not very mechanically inclined.

 

[JMT]

I'm so tired of messing with this that I'm reduced to watching this guy on YouTube and working on smoking my new Savanelli pipe.

You want to talk about a hobby teacher that will put you to sleep. Good teacher though!

 

[bobthetj03]

Wonder if those bare wires on the Elocker are grounding out under load and partially engaging the locker enough to cause that noise? It couldn't be that easy, could it?

 

[JMT]

Wonder if those bare wires on the Elocker are grounding out under load and partially engaging the locker enough to cause that noise? It couldn't be that easy, could it?

I wonder the same thing. I'm going to re-install everything first and just leave the locker disconnected. That will answer the question once and for all. One can only hope it's that simple. I've thought all along this is something simple, something stupid, something I will kick myself for.