Chattering noise while coasting

There are scratches on the case but they are faint. Even with the shafts held straight there is enough slack to where I'm not comfortable with reinstalling the existing chain.

I have been wondering about the design of this case and how the chain is not tensioned. Is there any reason why New Process did not design this case with a tensioner? It wouldn't fix the issue but it would at least help with chain chatter when the chain is lightly worn. Anyone have input on this?
 
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Buddy_Holly said:
I have been wondering about the design of this case and how the chain is not tensioned. Is there any reason why New Process did not design this case with a tensioner? It wouldn't fix the issue but it would at least help with chain chatter when the chain is lightly worn. Anyone have input on this?
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Sure, I've got some input. It added cost. And in the automotive world, design quality is often (almost always) ignored in favor of lower cost.
 
It's irritating how cheap manufacturers can be. Other than cost I can't think of anything. I'm beginning to think about how I can fab up a tensioner assembly for it.
 
I have no idea if it will. I sure hope so. If a tensioner can be fairly easily made then its worth the work to me. :driver:

I haven't done enough research to make something while its apart this time. Maybe I can make something when I do the SYE later on.
 
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Or D300. Its a pretty simple swap and gives you more rear driveshaft length and better driveshaft angle.
 
I like the d300. I hadn't even thought about it until now. I'll start reading up on it. Newb question, but how much shorter is it than a 231 w/SYE? I thought I saw 4" but there is conflicting info.
 
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The jeep is back together and driving but the damn chattering noise is still there. The drivetrain feels less sloppy now though since the chain was replaced and driving in 4hi is significantly quieter. The noise seems quieter than before but I'm not sure since the fluids were still cold during my test drive. It used to only make it when everything was up to running temperature. I'm going to take it to Lee's (transman731) shop tomorrow to have him drive it if he has time.
 
Buddy_Holly said:
I like the d300. I hadn't even thought about it until now. I'll start reading up on it. Newb question, but how much shorter is it than a 231 w/SYE? I thought I saw 4" but there is conflicting info.
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It is almost exactly 4" difference. I put a dana 300 behind an AW4, replacing a sye 231, and had to lengthen the rear and shorten the front within 1" of eachother based on a 4" difference overall (in an XJ) If that makes sense. In a TJ, this would make good sense considering the rear driveshafts are so short. This was years ago so don't take the measurements as gospel. Good upgrade but expect it to be pricey.
 
XJsavage said:
Good upgrade but expect it to be pricey.
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It's still cheaper than an atlas. I can justify the price of the d300 since it brings so much more to the table than the 231 in terms of design and aftermarket support. Plus I like the idea of having twin sticks :D
 
I've done the NP231 to D300 thing twice and about to do it for a third time. Only thing I don't like about the D300 is the popping in and out of gear when engine braking and downhill (not every D300, just everyone I've ever seen, haha). Everything else about it is better.
 
Yeah they are nice. Roughly the same crawl ratio as what you have. One thing I've noticed about any gear drive transfer case is they do and can create some heat. If you use a full syn gear oil like Amsoil 75-120 or close to it it will make it much smoother and run cooler.
 
jeepinmatt said:
I've done the NP231 to D300 thing twice and about to do it for a third time. Only thing I don't like about the D300 is the popping in and out of gear when engine braking and downhill (not every D300, just everyone I've ever seen, haha). Everything else about it is better.
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Do they pop out of gear in all selections? or is it just a 4hi or 4lo thing?

XJsavage said:
Yeah they are nice. Roughly the same crawl ratio as what you have. One thing I've noticed about any gear drive transfer case is they do and can create some heat. If you use a full syn gear oil like Amsoil 75-120 or close to it it will make it much smoother and run cooler.
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One thing I had planned down the line was 4:1 gears and some sort of under drive setup in front of it. Northwest fab just came out with a new one that adds only 5" to the overall length. It should crawl great after that :smokin:



NOW, on to the results of my visit to TLC Transmission. Driving the jeep did not yield any noises (must have scared them away) but once on the lift, the "chatter" (it sounded more like a rattle outside of the jeep) was easily recreated. Lee crawled under the Jeep with a stethoscope and believes the noise coming from the transfer case (it was loudest there), although he also said there was some noise coming from the transmission. Thanks again for the help Lee.
 
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Buddy_Holly said:
Do they pop out of gear in all selections? or is it just a 4hi or 4lo thing?
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If I remember right, it was only the rear in low, but I could be wrong. And it may be different case to case.
 
jeepinmatt said:
If I remember right, it was only the rear in low, but I could be wrong. And it may be different case to case.
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I've had several D300 transfercases and only 1 has done the popping out of gear. I ordered a new detent pill and spring kit and all was well after that. The 1 that popped out of gear had a 4:1 in it and was used on a buggy where the others were all stock and used on slightly modified Jeep CJs without issue.
 
rockcity said:
I've had several D300 transfercases and only 1 has done the popping out of gear. I ordered a new detent pill and spring kit and all was well after that. The 1 that popped out of gear had a 4:1 in it and was used on a buggy where the others were all stock and used on slightly modified Jeep CJs without issue.
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The first one in my TJ also had a 4:1 and did it. Interesting. The one I'm working on now will be stock gears, so hopefully it will be fine.
 
Never really popped "out", just kinda popped in and out. It would pop out and immediately pop back in, jarring the jeep and making a loud noise.
 
That doesn't seem too bad. It would freak out passengers though :lol:

Matt, how are you setting your 300s up to run driver drop? Flip kit or cable shifters or both?
 
If you look through some of my old posts, you'll probably find a thread with pics. I'm a machinist and engineer, so I just make it up as I go.
 
Following up on this thread in case someone uses it for info one day.

The noise was driveshaft vibration. The slip yoke was rattling in the tail housing. In mid September I ended up tearing the tcase apart to put new bearings in. My trans mount was toast so I put in a poly one that was laying around. That amplified the vibration and clued me in to what was wrong.

I feel like an idiot for not realizing it was vibration. I bought an SYE and just had a DS made. It should all be going in the jeep in the next couple weeks. Gotta get ready for a Gulches trip in March :D
 
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