Back about 3 weeks ago I did a swap from the np231 to the np242 and since I did the swap I notice that the 242 seems to be much louder then the 231 was.It doesn't necessarily sound bad but I can diffidently tell that its much louder,almost like a gear noise like when in 4low or similar to it is about the best I can describe the noise.It shifts easy and I have changed the fluid in the case 2 times since I put it in and it still sounds about the same and hasn't gotten any louder and it sounds the same whether its cold or hot.The case is said to have about 120,000 miles on it and all the shafts don't have any play to them and the chain seems to be ok also so I'm not sure what to think.

I have never been in a Jeep with a 242 to compare the noise so is the 242 just a louder case then the 231 or what?

 

I have had 2 of the 242's. One was remanufactured. They do make a 'whine' in 4Lo, but my 231 did also. When driving on the street in 4 Full-Time I can also hear it.
Does it sound funny in 2-HI ?

 

It sounds about the same in all the gears.My 231 was quiet and I only could hear it in 4low.

I am just kinda curious because I got a 3000 mile drive to do this spring and the last thing I need it for a catastrophic disaster to happen in the middle of no where.

 

I do not hear my 242 in 2-Hi. And 4-Lo sounds very different from 4 Part-Time or Full Time.
Could it be a bearing noise?

 

Well I can defiantly hear it in 2wd so maybe its not a normal noise . It seems that I might just have to break it apart to find out then.

 

The major difference between the 231 and the 242 is that the 242 has a "Differential" that enables full time 4x4. The differential is a poor design. It incorporates parts that run steel against bronze. Chunks of the mode synchronizer teeth get chipped off when being improperly shifted to Full Time (grinding) and end up being imbedded in the bronze ring in the differential. Makes lots of noise when full time is engaged.

These differential internal parts are nonprocureable and a new differential costs around $500.

When you drain the TC look for little bronze flakes floating around in the ATF.

Change TC ATF often.

 

No flakes were in the fluid when I changed it,it was pretty black but not the worst I have seen.

 

I have never drained dark fluid from a TC.
What caused it to get burnt? If it was not the transmission that overheated and transferred the heat, than it could be another reason to think it's a bearing.

An infra red temp gun may be able to pinpoint it if it is one of the outer bearings. If it is the front output bearing than removing the front driveshaft will prevent it from turning in 2-Hi.


To CCken, Thank You very much for the informative post!

 

When I say it was "pretty black" it wasn't like motor oil if thats what you thought I meant.It was still red just not as red as I would of keep it if it was me keeping up on the changes.I also got under there after a 60mile drive at 70mph and felt around on it to see if it was getting hot anywhere and it wasn't to hot at all really,no where near as hot as I thought it would of been.

The case did sit in the guys garage for about 2 year before I got my hands on it so...

 

After driving this thing around for awhile now I have came to the conclusion that I think I'm going to have to pull this 242 back out and tear it apart to see whats going on inside.For some unknown reason to me its loud when its in 2wd but not when in 4full time which make about zero since to me.Also when its in 2wd if I push on the lever forward and put pressure on it I can hear the noise get louder and kinda feel the noise in the handle and I'm not sure what to think about that ?? ??

So have any of you guys experienced this before? Maybe give me some pointers on what to look at inside this thing when I get it apart that would cause this.I'm thinking it has to be something with the shifting mechanism but not really sure.

 

I have the 242, and it's quiet in 2wd. It does make a little noise in 4wd though. I would definitely get it checked out if I were you, or switch back to a 231. I personally have plans to switch to a 231 once I get the money. I don't really use the 4wd full time option, and I only use 4wd hi and lo off road.

 

Got it out and apart and it seems the pump is pretty scratched up inside.Looks horrible to me but is this the normal way they look after they get used or is it done for?