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Chain slap NP231

My 99 TJ has been making some interesting noises/vibrations lately. Had it out on the trails this weekend, and when alternating the clutch/gas (climbing something, usually) I got a lot of... rattle... I guess you could call it. The guys from the shop that's been doing the work lately said that didn't sound good. Eventually they agreed it sounded like "chain slap" from the transfer case.

They called another guy who knows these x-fer cases inside and out, and he seemed to think it might just be natural "gear slap" and not a big deal. UNLESS, he said, the front driveshaft can be rotated "more than just a little" while in gear. I jacked up the front, put it in gear (4Hi) and found the front driveshaft rotates between 1/4" and 1/2". That's a guess as it's hard to determine distance during rotation...

SO, if it is chain slap (and if so, it sounds pretty bad) what do I do? Do I buy a new NP 231 or rebuild this one (adding a tera-low kit, obviously)? My TJ only has 48k miles on it. I can't believe this would happen so soon -- and the sound has been there for the past 20 thousand miles. It ONLY happens in 4Lo and ONLY when I alternate clutch/gas/brake in quick succession.

Money is an issue... thanks guys.

Eric

99 TJ SE
Reply to
Eric
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Reply to
L.W.(ßill) Hughes III

So what the heck do I do? Is there a way to "fix" it???

Reply to
Eric

Reply to
L.W.(ßill) Hughes III

The T case does have a certain amount of play, and I think what you described is within spec because that's about what I have and I don't have any rattling issues.

Now, you said it only happens in 4lo. You might look at your Tcase shifter linkage, you might not be getting it all the way into 4lo and your linkage could be needing an adjustment. Barring that, it might be your planetary gear assembly. Once I pulled my T case into 4lo and got a strange "rattle," it sounded like gears clashing, but the T case wasn't all the way in 4lo. At any rate, I don't think it's your chain.

Reply to
Matt Macchiarolo

Only fix I know of is to change the chain.

Reply to
Will Honea

It's never leaked that I know of. I'm going to change the fluids here in a couple of weeks anyway. I'll see if it's low.

Also, I have a new... vibration.. that's all I can describe it as. When I'm going down the road and have a load on the engine (i.e. normal driving) the whole TJ buzzes. When I press in the clutch it stops, so I know it isn't tires.

I just had that SYE/driveshaft installed, as well as having my tailpipe cut at the downward bend just behind the axle (it was hitting my shock). Any thoughts on what could be causing this?

Reply to
Eric

I doubt that it's the chain. I have seen these chains get sloppy, and they make one hell of a racket banging against the case, and it isn't only in

4LO. The ones that I have seen fail were due to prolonged operation with no lubricant, and the bad chain was just the symptom.

I am with the other dude that discussed your linkage and the possibility that you aren't fully engaged in 4LO.

Reply to
Jerry Newton

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