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ZJ NV242 Transfer Case Swap

Author: Swamp Boy

Ok fellas... Here it goes...I did it...It works...All is well!

First thing you need to do for this swap is go to a bone yard and find a donor. Either an XJ or ZJ NV242 will do. 242's were available in 80's model XJ's and all models of ZJ's (as an option) so look in them all. Keep in mind that ‘93 ZJ's did come with this as an option so keep looking in them if you see one in the yard. But they are very common on XJ's. I found around 20 XJ's and 6 of them had this case. All you have to do is look at the shifter. It should have - 2WD - 4 Part time - 4 Full time - N - 4 Lo.

There you have it...


You don’t have to be a mechanic to do this job. It’s really not that hard. I think it took me about 14 hours total (over 2 days - half a day one day and the whole day the second). But I did a lot of reverse engineering you will not need to do.

Let's get started!
Here is my donor. It came out of an '89 XJ with 65,000 miles on it.

donor transfer case

I cleaned it up and made sure it went smoothly into all the gears.

Then I pulled the 249 - don't worry, it's not really that hard.
Drop your front shaft.

front drive shaft

This is a very important part... Chock your wheels... Chock your wheels... Chock your wheels...

Are everyone's wheels chocked???? Good, let's continue.

Drop your skid if you have one. It's only three bolts. Not that hard, is it?

Then remove the rear shaft

rear drive shaft removed

Put a jack under the tranny (right behind the pan). Remember to leave yourself room to remove the cross member. Now remove the cross member. There are two bolts on each side and one big one in the middle in the tranny mount. I didn’t take pictures of this because I thought you could figure it out....

Remove the transfer case. I didn’t get any pictures of this step because its a pain to take pics while on your back under a truck, but there are 6 bolts - 15mm If I remember correctly.

If you can’t find them, skip this step and drink a beer. You cannot do this mod!

Then you drain the T-case. I did this cool design on my driveway...

fluid design

Here is the old 249 on the ground

old 249 transfer case

At this point, I drank some beer because that was it for the day.

Before you ask, it did not take all day. I didn’t get started till almost 5 pm and got the transfer case out in about 1 1/2 hours. (Conservative - it probably wasn’t that long, but I had trouble with one of the bolts. Hint: ON top...)

Another hint: Use deep well socket. The studs stick out too far for a shallow well socket and you could waste a lot of time trying to use one. Don't ask me how I know.

Okay, so this is the part you need.

new 242 transfer case

There is a cover over it. You can’t miss it. Then there are a few snap rings under that cover. You will have to remove this plate. Its on the tail shaft…again you will see it.

tail shaft

Remove the speed-O sensor that is right next to this. (Just pull it out and put it on the side out of the way.)
Now back to your hole...

Inside there is a snap ring. Here is where the good pair of snap ring pliers come in. Loosen all the screws on the cover and break it loose. Use a hammer and screwdriver as it’s RTV'd. Grab the snap ring and slide it off as you slide the cover off. Once that is out of the way, take out the bolts in the center of the case and break it open.

You will see this inside.

interior of transfer case

On the left side behind the shifter that you see slid down, is the sun gear you need. You will need to tap the input slightly to get it out.

Here is what it looks like out of the case.

planetary sun gear

You don’t have to remove it from the planetary gears. You can use the whole set, but I decided to pull mine out and look at them. See me with the snap ring pliers. (GOOD ONES!)

So now that you have completely taken the 249 apart, it will be a breeze to take the 242 down.

Make sure you do it on a clean surface! When you get the 242 apart (pretty much the same) make sure you pay close attention to how you are doing it. You will notice the innards of the 242 aren't much different.

There is a huge shift mechanism with 2 shift forks.

disassembled NV242

To remove these shift forks, start by moving the shift linkage to the top. I'm not sure which way you have to turn it, but you will see. There is a pin on the shift fork that hooks to the swing linkage on the inside of the case. I used a pry bar and wedged it in between them. Use just enough pressure to pop the shift fork pin out and slide it up. When this is done, shift the T-case again and the lower shift fork will pop out and the sun gear will come out at the same time. Don’t forget to take the front cover off and remove the snap ring first.

Install the sun gear out of your 249 It will take some tapping - I used the hammer handle. Make sure its fully seated.

Okay, I guess I left out a part on both of the break downs - the chain. It removes by sliding one of the gears up the shaft and off it will come. It goes on pretty easily.

249 input on the 242

Here's the 249 input on the 242.

On reassembly use RTV. I went a little overboard, but here it is bolted back together. (I did cut the excess RTV off with a razor when it dried.)

In this picture you can see the short shift linkage from the 242 lying on the floor and the 249 linkage on the transfer case.

shift linkage


So I put the 242 shifter linkage back on.

Install your new T-case and put the selector in 2WD and switch the T-case into 2 wheel drive. Adjust the slide nut on your linkage so that you can hook the linkage up. That should work for the full throw. I had a buddy shift back and forth until I had it adjusted correctly.

If the donor T-Case is from a '93 or newer, you can just plug the shift indicator in. If it’s not, then you will need to buy the part from Jeep (as soon as I do I will post the part number) The speedometer sensor is another concern in a pre '93 T-case. Your sensor out of your 249 will work and obviously will plug in.

On the inside of the truck remove the radio bezel (6 philips screws) and pop it out. There are 3 philips screws in the Vehicle Info center. Pull it out and you will see two sets of plugs, a red one and a black one. I think the red ones where hooked up but I’m not sure. But the point is, whichever ones are hooked up, unhook them and hook up the others.

That's it! Make sure everything is tightened up and fill your transfer case with fluid.

Then try it out…

Mine did this…


If you have any questions, be sure to ask!

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