Just pulled the case off of the differential and watched the gears move while the truck rolled forward and backward about ten feet. There was no metal shavings in the oil, but someone had been in there before me. When the truck was rolling forward, I would stop and inspect the gears to check for chips and cracks. There were no signs of any of these problems. After looking at this, I am convinced that the transfer case is the culprit. I am probably going to take the transfer case off this weekend and pull the cover off and see what is happening. At least its not the gears in the differential. Does anyone have a good source for transfer cases?

 

You might want to take a look at the hubs before diving into the transfer case. They are the auto locking type and I would not have too much confidence in them.
I'm not sure if there is a manual locking type to replace them with. That is the way I am gonna go with my clunk.

Also try putting it on gravel and see if the clunking gets better or goes away. If it goes away we have the exact same issue.

I just don't want top see you do more than you need to while trying to fix it.
I think you will need some pullers to get the case apart. Unless you are tooled up to do so it might get fustrating real fast.

Where are you located? I kinda wish we could work together on this one.

 

OK.. upon further evaluation. I was just playing around with my truck. It seems all the clunking is coming from the transfer case area.. It might be the shaft but, when I twist the forward shaft it rotates about 30 degrees and makes a kinda clunk inside the case when I twist it hard. there has to be something going on inside the case.
I had a someone shift btwn D and R while I watched the driveshaft. It seemed to engage then twist back then go back forward and give the hard clunk. Almost like it had resistance to start then went past something holding it then hit something solid. It acted like an internal gear might be lose on the shaft and then binds up.

I hope that it is something simple, but I fear a rebuilt case might be in the future.

I'm pretty sure you will find something inside the case if we have identical issues.

-Dave-

 

I believe that we are on the same page. My noise is coming from the front, so it could be the hub. Since it is the transfer case that is leaking, I think that is where the issues are. How hard would it be to pull the hub out? The transfer case is not that bad aside from the weight. I can tell you that there is no amount of gravel that will fix this problem. You can clearly hear gears clunking around where they should not be. This is not like the "grabbing" that happens while turning in 4WD, this is a bad noise. The real fun is going to be finding a transfer case for under 500 bucks...

 

Like I said in the second post last night, I think the xfer case is the issue.
The way I determined this is, engage the low range so you get a good clunk. Have someone in the seat shifting btwn D and R while you watch the CV joint (turn the wheels so you can see it easier).
If you don't see the CV joint moving while going from D to R it is not gonna be the hub or the CV or the diff. Make sure the person in the seat is holding the brakes tight so it don't roll.

When I tried this last night I could see the forward drive shaft moving quite a bit. The noise was definitely coming out of the case. It makes more noise while in low range. I also saw the rear shaft moving some, but I think that is just the rear u-joints.

I have been searching around for a case to put in my truck. I have found a 3.9 equipped 1990 Dakota that is being parted out. I'm not sure if it will work in my transmission. I'm pretty sure the cases are all the same. The NP231 is a real common case so, it will not be too hard to source one. You might be in over $500 for a rebuild. The best bet is getting one from a salvage yard.

-Dave-

 

take it out and apart,it most likely needs a chain in it,its not brain sugery to replace the chain,the chain turns all the time on a 231 case,and high miles equals a worn chain,with all for wheels of of the ground,put the case in netrual and rock the front and rear shafts back and forth,lots of play equals a worn chain
rhad

 

Yeah.. I just got off the phone with a professional and he said the same.
Most likely the chain.. that is kinda what I was thinking from the start.

I am gonna be taking mine apart this weekend also.

-Dave-

 

I am going to be doing the same thing. I was wondering since the chain turns all of the time, why does it only make this noise while in 4WD? I am just thinking out loud, I am 99% sure that my problem is in the transfer case. I found someone that will do this for about 350 for a complete rebuild.

 

If you listen close while in 2wd you might hear the chain slapping as you roll. At least mine does. It is definitely loose.
The chain is gonna cost me $77 and change from a local shop.
I have been told it can be done without taking the case out of the truck also. I am gonna test the theory and report back to you all.

Going to go buy my chain tonight. Wish me luck for the weekend.
I'll try to take pics of the job so 1st gen owners might be able to do it themselves and save some coin.

-Dave-

 

That'd be great.
We can always use easy to follow how-to's.