NP242

[Tuzmaster]

Hey guys

Looking around there doesnt seem to be much aftermarket support for the NP242 on the WJ's. Ill have to get an SYE of some sort on this build so the question is what?

1) There is possibly a full SYE kit for the NP242 for WJ's. Didn't see it on website or anything but will call to find out
2) There is a hack and tap kit where you cut part of the shaft off, slide a ujoint with a yoke on top of it, put a bolt through it after drilling the shaft and that is not your SYE
3) Change to a different tcase? like a 231?

What do you guy run on your rigs? Mine will end up with a 6" lift and 35's (at least).

Thanks all!

[Ted_Z]

Do you have a an I6 or V8? The V8 version of the 242 has a 32 spline output and is more heavy duty compared to the typical 27 spline found in all other jeep 242 applications.

There are options for the 27 spline version, but the 32 spline version is rare enough that there isn't much support.

I was able to build my own "hack and tap" like SYE for a 32 spline, using off the shelf parts, but I had to machine the tail cone to accept a new seal and machine the yoke flange.

I would say that swaping to a 231 would be cheaper in the long run, and have better support.

[Ted_Z]

Maybe these guys could offer something:
http://www.driveshaftsuperstore.com/SYE_Kits_$375.htm

[Tuzmaster]

Its the V8, but I have already swapped a NP242 into it out of an I6. It has the proper input shaft to mate the v8 45RFE transmission, but the rest of the internals are from an I6 242. Hence the debate. Is the I6 242 hack and tap strong enough for the 35" tires.

To give more info, it will be as mentioned 35" tall tires with 4.88 gears in the Diffs. I dont know if this helps but here is more info.

[Ted_Z]

The non-WJ 242 output shafts (and 231) typically fail at the spiral cut area that the speedometer gear rides on. The WJ 27-spline version is a bit stronger as there is no spiral. However, If you want to be sure it stands up to 35's, I'd upgrade it to a 32 spline SYE like this https://www.ironrockoffroad.com/prod...j-sye-kit.html

WJ main shaft:

Typical 242 main shaft:


The other alternative is to "upgrade" a 231 and install a HD SYE on it. You can also do some internal changes inside the 231 for more strength. On paper the 242 is still stronger than a 231, but its not and apples-apples comparison once you start messing with the guts.

If you are leaning towards the 231 route, I have a a SYE, 6-gear planetary and wide chain/sprockets sitting in my garage that I was going to sell on Craigs List but never got around to it. Granted they are used parts, but usable, plus I don't need much $ for them...

[K2]

If Tuz doesn't buy them I will. This will save us a trip to the junkyard!

[Tuzmaster]

-How difficult is it to put a 231 behind the 45rfe tranny? I imagine the mounting studs need to be rearranged, is that even possible? what about the input shaft? Is it compatable? I see an advantage long term in 231 for all of the aftermarket support.

-As for the 242, it seems the hack and tap is the cheaper way to go without much compromise in strength. Has anyone run this setup on their rigs?
-That HD kit looks promising, but will it work the WJ 242? besides the fact that there is a big hole for the speedo that needs to be covered it could.

Thanks guys for all of the replies

[Ted_Z]

How difficult is it to put a 231 behind the 45rfe tranny? I imagine the mounting studs need to be rearranged, is that even possible?
The 6-bolt pattern is the same for the 231, 242, 247 and 249

what about the input shaft? Is it compatable?
Your current input shaft will swap over so long as you use a 231 donor is '96 or later.

As for the 242, it seems the hack and tap is the cheaper way to go without much compromise in strength. Has anyone run this setup on their rigs?
A 27 spline H&T will never be as strong as a 32 spline HD version. Before the HD version was around, the only option was the H&T. I'd look over on a XJ forum for more real world experience.

That HD kit looks promising, but will it work the WJ 242? besides the fact that there is a big hole for the speedo that needs to be covered it could.
Iron Rock says it will fit, but you should ask them directly. As for the hole, just stick a speedo sensor in there. Then when you do an axle swap down the road, you'll be able to make your speedo work without the ABS tone rings.

[Tuzmaster]

I the guys at IronRock and hey said that there is a cap that comes with the kit to cover the speedo hole if not needed. So Ill go with that kit to beef up the tcase.

I do have another question regarding the 242. At one point i tried to take the front driveshaft yoke out and it would not budge. Right now its the CV style yoke and eventually ill replace it with the ujoint. Is there anything special about this yoke? some pin that has to be taken out before it slides out? After removing the nut it would not budge.

[Ted_Z]

Nothing special, just a big nut retaining it. There is a rubber star seal washer under the nut, maybe someone in the past used some RTV to make it stop leaking. I know I've done that

[Tuzmaster]

Okay, thats what I figured, Thanks guys! Ill get a pullet of some sort and just pull it out when the time comes. will end up rebuilding the case just to be sure it wont leak.