NP241D thoughts

[DirtyComanche]

So, assumably I could figure this out myself, but I haven't got that far yet, and I figured it had been a while since I had made a thread of any sort.

 

Anyways, the tcase in my dodge broke. It was, and still is, really inconvenient. However, I now have a 'spare' wrecked NP241D. It's from behind an auto and a cummins, I can't confirm it but it might actually be more like a '241HD' rather than just a 'D'. I need to take it apart and asses the damage, but if I only broke the shift collar I would probably get a new one and not return the tcase for the $250 core value. Oh, it's driver's drop, later dodges were.

 

So, now, can I bolt it up to my 23 spline AW4? I know, as-is, I can't. The input on the NP241D is a 23 spline variant, if I counted correctly, but I am unsure if the pressure angle is the same as on an AW4 (I would assume so). It is probably too long, as a dodge 47RH output shaft is flush with the aft face of the tranny, and an AW4 protrudes about 3/4" (by memory). Novak offers an adapater (I think) that will allow a guy to bolt the two together (but it's not stated to do what I want, it's for something else). It is basically a round spacer, about 1" thick, and it offers provisions for clocking. Alternatively, I think I could cut the input on the NP241 down on the lathe, since the end result would basically be the same. Or, I am starting to guess, the input from my junker 23 spline NP231 could be swapped on without any hassle.

 

Now, the other problem... I have a NP231 HD SYE. Yay. I won't be running a NP231 again, and selling a used SYE is pennies on the dollar. Anyways, a 231 HD SYE is basically a NP241 mainshaft that has been cut down and tapped, and a new tail-housing. Or at least the first HD SYEs were made this way - but I can't confirm if they modded anything else on the shaft. This leads me to think there is a chance that I can put the 231 HD mainshaft in the 241 case. I might be totally wrong - I do not have a 231 here to check with. Visually, the 241 chain-case looks to be wider, assumably to accomodate the wider chain. Again, I don't have a 231 to compare. This I think would be the only potential problem, unless I've missed something else. If the chaincase is considerably wider, the 231 HD mainshaft might be too short.

 

So, why am I trying this? Well, the NP241D (or the one I have at least) has a 32 spline front output, along with the same for a rear output. I have the front flange to put a 1350 CV on the front of it already. I could buy one for the rear for a reasonable price. The tcase seems to make economical sense - if it will work. Wider chain, 6-pinion planetaries, HD outputs, apparently stronger casing, and it only weighs about 85lbs or so. I broke a 231 front output before, and hadn't come up with a decent option, save blowing tons of money on an upgraded D300 or buying a stak or atlas (money money). The other problem with all these cases is they shorten the front driveshaft, which isn't really ideal in an XJ/MJ platform. It seems like it should only cost me a rear flange for a 1350 CV, and perhaps the spacer and perhaps a NP241 SYE kit (if nothing else).

 

So, thoughts? No, I wrote too much, nobody is going to read it... I should just do my own research.

[pingpong]

By the way it sounds.. you have it figured out. Now it is just a matter of mating it up. I also thought that upgrading the planateries was available through JB conversions. They did something with the dodge case and jeep cases if I remember right. Still early in the morning...just got off work.

[TNT]

They will swap and it is way stronger then a 231 case. You will either need a hack amd tap or a different style HD SYE.

 

Dodge used a 23 and a 29 spline input shaft on a Cumins powered trucks. The input might also be longer so you might need a clocking ring, It will add the needed space and allow you to rotate the transfer case to increase ground clearance. If no spacer is needed you might be able to redrill the trans adapter to clock it higher.

 

Start getting that baby ready to swap. Your 231 would make a good box for rocks underdrive too. :brows:

 

:cheers:

[DirtyComanche]

The input might also be longer so you might need a clocking ring, It will add the needed space and allow you to rotate the transfer case to increase ground clearance. If no spacer is needed you might be able to redrill the trans adapter to clock it higher.

 

Start getting that baby ready to swap. Your 231 would make a good box for rocks underdrive too. :brows:

 

:cheers:

 

 

 

The plan if I kept the 231, which I didn't want to do, was to redrill the AW4 to clock the case flatterish. It can be done. But, the input for the 241 is too long. The clocking ring is money... So the first plan would be to see if I can viably shorten the 241 input, or swap the 231 23-spliner I have.

 

I kicked around the idea of a box4rocks, or madrooster, or whatever... I don't know if I can make it fit well, and if I actually want one. I'm going to try this driveline in my XJ first, and the rear axle is staying in the mostly stock location I'm more opposed to buying one because they cost money, and I question the strength of a 241 behind one. Yes, the 241 came stock behind a cummins... That doesn't mean they don't break them. At the same time, it's not like this setup should be much weaker than an upgraded D300.

[TNT]

The input might also be longer so you might need a clocking ring, It will add the needed space and allow you to rotate the transfer case to increase ground clearance. If no spacer is needed you might be able to redrill the trans adapter to clock it higher.

 

Start getting that baby ready to swap. Your 231 would make a good box for rocks underdrive too. :brows:

 

:cheers:

 

 

 

The plan if I kept the 231, which I didn't want to do, was to redrill the AW4 to clock the case flatterish. It can be done. But, the input for the 241 is too long. The clocking ring is money... So the first plan would be to see if I can viably shorten the 241 input, or swap the 231 23-spliner I have.

 

I kicked around the idea of a box4rocks, or madrooster, or whatever... I don't know if I can make it fit well, and if I actually want one. I'm going to try this driveline in my XJ first, and the rear axle is staying in the mostly stock location I'm more opposed to buying one because they cost money, and I question the strength of a 241 behind one. Yes, the 241 came stock behind a cummins... That doesn't mean they don't break them. At the same time, it's not like this setup should be much weaker than an upgraded D300.

 

You can get one here for $55.00

http://www.pirate4x4.com/forum/showthread.php?p=9096802

 

Here is a DYI4x4 link for one for $62.00

http://www.pirate4x4.com/forum/showthread.php?p=9096802

 

It shows a good view so I bet you could duplicate it.

 

I hope that might help.

 

:cheers:

[DirtyComanche]

Thanks for the links... For $55 US, I can't really say no... Novak wants more than twice that.

 

Either way, we'll see if I need it.

[carnuck]

I'm tired so I didn't read the whole post. Diesels came with both 23 and 29 splines (3 speed autos are 23). Count and save yourself a headache! The 4 speed auto changed the angle of the splines so they may not swap (@'97 the change was made)

[DirtyComanche]

Well, it's a 4spd auto (47RH) out of a 94... It's definatly 23 spline. I counted twice, and confirmed it...

 

I had thought they might have changed the pressure angles on the splines eventually. If you say it was in 97, that will save me... But I should look into it.

[carnuck]

I have the 241 OR from a Rubicon for mine (4:1 low range)

[DirtyComanche]

Yeah, I'd like one of those if I could easily get one...

[carnuck]

Easily, yes. Expen$ive, you bet! $1500 new or $900 used here all day long (with the Canadian dollar being up, now is a good time to buy too!)