NP242 rebuild with upgrades

I found a thread link for a guy who got an AMG shaft machined for an SYE. He's using one of the super-short SYE housings. The HD shaft necks down between the bearings and the output splines, so this is the only way to machine it, and you have to use the super short housing.

242SYE1024.jpg


Near as I could tell from that (without reading everything) it looks like he got Novak to cut the shaft. Its probably the same thing Tom Woods does. The housing bolt pattern for the 242 is different though (four bolts on the NP242, instead of five on the NP231), and I don't know who makes a 242 super-short. Also notice there is no boss for the speedo.

Starting to think, just do a HnT on the output splines, but that raises another issue of finding a yoke for it (the front 32-spline output does not mesh; I have not tried the normal HnT yoke but I can soon).
 
Last edited:
So, I am the guy with the above Transfer Case (my case, my photo). I was one of design team who did those, that case was first one done. That particular output housing and shaft are both new from billet material.

FYI it is my understanding that the pitch change was made only for NVH (Noise, Vibration, Harness) a common buzz phrase in the automotive world these days. I'm not sure where the strength numbers posted before came from unless they were extrapolated from the linked site with the industrial type chain listed. I just glossed over the thread so if I missed something I apologize. There are two widths and two pitches of chains with the thrown in odd variable of the rocker joint. The AMG cases are quite a bit more substantial than the regular version. I have both in my shop disassembled and can compare any pieces necessary.

There is some good info on this thread and some mis-information as well. I'll try and read through and post a follow up with the correct stuff I have.
 
jpndave said:
FYI it is my understanding that the pitch change was made only for NVH (Noise, Vibration, Harness) a common buzz phrase in the automotive world these days. I'm not sure where the strength numbers posted before came from unless they were extrapolated from the linked site with the industrial type chain listed. I just glossed over the thread so if I missed something I apologize. There are two widths and two pitches of chains with the thrown in odd variable of the rocker joint. The AMG cases are quite a bit more substantial than the regular version. I have both in my shop disassembled and can compare any pieces necessary.

There is some good info on this thread and some mis-information as well. I'll try and read through and post a follow up with the correct stuff I have.
Click to expand...


Wonderful! I'm the source of much of the misinformation I'm sure, digging for details about those chains was quite difficult.

The chain stats were extrapolated from multiple sources including borg warner documentation. If you have additional details, please add them!
 
I'll try and take time to read though it in a bit. Unless you are really putting a lot of power through a case, I honestly don't think chain strength is the weak link as long as it is a fresh chain. The analogy I always used was that of a front wheel drive timing belt, excellent way of controlling the timing components as long as they are maintained and replaced as required. Failures on chains usually only happen when they are stretched and way past their expiration. That said, I run an AMG 242 and love it. I am putting 500hp (soon to be 600hp) through it and I suspect that may be an application necessitating the wide chain and upgraded components. Your average XJ 242 with a fresh rebuild, output shaft for sure is the weak link.

There are lots of variations with the 242, from the AMG on the top end down to the average XJ type (or the liberty if you want to count that). Some pieces will cross over others will not. If you have specific questions, fire away.
 
Now that I'm too late, somewhere here I had read of a swap using the chain and sprockets from an NP241 as being easy drop in fit.

Anybody?

I picked up a spare 242 awhile back, need to gut it for a shaft to send Tom Woods.
 
Randy_66 said:
Now that I'm too late, somewhere here I had read of a swap using the chain and sprockets from an NP241 as being easy drop in fit.

Anybody?

I picked up a spare 242 awhile back, need to gut it for a shaft to send Tom Woods.
Click to expand...
That does not sound correct. If I remember correctly, the drive sprocket on the 242 has a different inner diameter than the 241.
 
So based on what you all have found, what year/model case would be best to start with? I need something with mechanical speedo so that pretty much makes it just up to the mid-90's somewhere. Input preferred is 23 spline medium length, but that is easy enough to swap if I have it apart. At this point, I'm looking for like a 90-95 or so XJ or ZJ case. Any refinements to my search?
 
I used a 98 ZJ case (242j) and rebuild kit, and the differential came out of a 242hd from a 2002 Dakota. I saw no advantage to the 242hd differential other than an extra bronze bushing in the differential. I used the Dakota differential because the ZJ diff was sloppier and I had the Dakota case torn down already. I had to swap the drive gear sprocket from the ZJ diff to the Dakota diff because I used the 1" chain on the tom woods shaft.

What's different about the mechanical drive and the electronic drive? I'm pretty sure the hole the drive goes into is the same.
 
xeroOTG said:
I used a 98 ZJ case (242j) and rebuild kit, and the differential came out of a 242hd from a 2002 Dakota. I saw no advantage to the 242hd differential other than an extra bronze bushing in the differential. I used the Dakota differential because the ZJ diff was sloppier and I had the Dakota case torn down already. I had to swap the drive gear sprocket from the ZJ diff to the Dakota diff because I used the 1" chain on the tom woods shaft.

What's different about the mechanical drive and the electronic drive? I'm pretty sure the hole the drive goes into is the same.
Click to expand...

More research over the weekend and I found that you are correct about the mechanical vs electronic - the housings appear the same and the only difference is what you stick into the drive hole. The parts are interchangeable. So that opens up my search. The 242 in my WJ does appear to have a different tail housing, so those are out of my search. So I'm looking for anywhere in the 90's XJ/ZJ 242. That opens up a lot of options. I see many more ZJ labeled cases than XJ cases. The only one I have found local though is from a '88 and it has a short 21-spline input and he want's way more than I want to spend on something.

There has to be someone in AZ parting out something with a 242 in it. Wrecking yards all want a core. I wonder if I could give them a blown up 229...?

According to this guy - http://www.ebay.com/itm/NP242-242-D...m280c4dc7e7:m:mdTPw8S-9zd-qcIyz96lxLQ&vxp=mtr - this diff will fit the J case. Thoughts?
 
DieselSJ said:
More research over the weekend and I found that you are correct about the mechanical vs electronic - the housings appear the same and the only difference is what you stick into the drive hole. The parts are interchangeable. So that opens up my search. The 242 in my WJ does appear to have a different tail housing, so those are out of my search. So I'm looking for anywhere in the 90's XJ/ZJ 242. That opens up a lot of options. I see many more ZJ labeled cases than XJ cases. The only one I have found local though is from a '88 and it has a short 21-spline input and he want's way more than I want to spend on something.

There has to be someone in AZ parting out something with a 242 in it. Wrecking yards all want a core. I wonder if I could give them a blown up 229...?

According to this guy - http://www.ebay.com/itm/NP242-242-D...m280c4dc7e7:m:mdTPw8S-9zd-qcIyz96lxLQ&vxp=mtr - this diff will fit the J case. Thoughts?
Click to expand...
I say definitely yes on the 6 pinion. Also, have you considered eBay for a whole case? Even if an ebay 242 is blown, you should be replacing all of the seals, bearings, and chain. If your doing the tom woods HD SYE your going to only be reusing half of the case anyway.

Also, some ZJ cases have a 32 spline front output, whereas the XJ case is a 23 or 27 spline.
 
xeroOTG said:
I say definitely yes on the 6 pinion. Also, have you considered eBay for a whole case? Even if an ebay 242 is blown, you should be replacing all of the seals, bearings, and chain. If your doing the tom woods HD SYE your going to only be reusing half of the case anyway.

Also, some ZJ cases have a 32 spline front output, whereas the XJ case is a 23 or 27 spline.
Click to expand...


I have been looking there, but adding the $85 shipping drives them into costing a stupid amount for something that I am going to rebuild. I think I have a high-mileage ZJ case from there though.
 
I picked up a 1990 vintage NP242 from a guy in the local club. Interesting thing, the rear case half has some kind of tube fitting on the top at the drivers side. Could be useful for a little 12v cooler pump return. The inside is closed, but it could be opened with a drill pretty easily. Its just above the front output bearing.

1990_NP242_Tube_Inlet.jpg


Might not work that great since it is above the fill port, so there would have to be some air in the cooler line by necessity, but if it just kicked up at the end and the rest was full of fluid it would work alright.
 
Re: Re: NP242 rebuild with upgrades

ehall said:
I picked up a 1990 vintage NP242 from a guy in the local club. Interesting thing, the rear case half has some kind of tube fitting on the top at the drivers side. Could be useful for a little 12v cooler pump return. The inside is closed, but it could be opened with a drill pretty easily. Its just above the front output bearing.

1990_NP242_Tube_Inlet.jpg


Might not work that great since it is above the fill port, so there would have to be some air in the cooler line by necessity, but if it just kicked up at the end and the rest was full of fluid it would work alright.
Click to expand...

While your at it, you could drill out the upper drain hole too. Neat find! Does it have a casting number?
 
Good morning everyone, and congratulations on your forum that I follow regularly, especially when I have to do the usual node restoration work on my Jeep, i come from Italy, Lucca City.
I am passionate for about 20 years and I own 2, a CJ7 ANC 304 and one ZJ 5.2 V8, but I have owned for many years also a XJ 2.1 TD.
It drew much attention this thread as I am about to replace my TC with a NP249 NP242 which I consider much more practical and functional.
For now I just changed the VIC, the bezel and the gate on the lever.

Normally all NP242 reducers are the J or HD, my hand is a NP242AMC as you can see in the attached picture, this is the problem, before mounting it I would replace the chain and change its bearings and seal, for the chain I seem to have understood that it is a HV061 with rocker joint that rieesco not find the net, and then the other problem is finding the bearings and seal kit, because I have not yet figured out if you need to input gear 16mm or 24mm.
This thread is the only network that I could find as are other times just in your forum you can find other interesting changes also well detailed with photos.
I gently ask if you can give me some advice on this species on the bearing set for this 242AMC, and also for the chain.
I am attaching some photos so that you can give a good evaluation.
My best regards to all and thanks for your time.

Master7
 
Last edited:
How can i do for pics insert?

aH!!! OK OK I had see..."You may not post attachments".
Just i can i will insert my photo of my NP242AMC (ECE for Italy xj).

Master7
 
Last edited:
xeroOTG said:
The only hv-061's left in the country are available at Novak. They had 5 last month and they're overpriced. I spoke to an engineer at Borg-Warner Morse who said once those chains ran out they have a vendor they work with who can make new ones which is ironic since BW is the OEM of the links that the vendor would end up using anyway. If you need those details let me know.
Click to expand...


What kind of chain can be mounted in place of the HV-061? The'm trying but I also can not find it because it is out of production. Thank you for your time. Master7
 
You must log in or register to reply here.

Similar threads

J
Whine after transfer case rebuild.
Replies
0
Views
129
jshultz78
J
C
NP231 Rebuild with SYE
Replies
7
Views
234
ChillyB
C
T
Anyone experience this issue with a Detroit Truetrac?
Replies
10
Views
443
Evan03
E
B
NP242 front output stuck
Replies
1
Views
144
Tim_MN
Tim_MN
G
1996 Cherokee XJ Stock For Sale
Replies
0
Views
191
gundog
G
Back
Top