Finished 242 swap and problems

[SBpunk]

1992 Comanche 4.0 AX15

 

I swapped in a 242 from a 1996+ and realized the output shaft/rear drive shaft was insanely long. Ended up cutting down the output shaft and still wouldnt fit. Cut off about 2 inch off the slip yoke on the drive shaft and everything fit just fine.

 

I took her out for a test drive and noticed at lower speeds I'm getting a noise when giving it gas that almost sounds  like something is rolling around in the truck bed but coming from under my feet. Nothing in the bed by the way. Also when I was turning I would get a strange vibe, not like a death wobble, randomly. I'm thinking the slip yoke either shouldnt have been cut, the input shaft is messed up (med on case short on trans) or both. 

[mikekaz1]

Following...

[SBpunk]

So have some decent play in the rear drive shaft where it meets the tail shaft. So time to start researching if I can swap some parts around from the WJ one that I bought on accident. Hoping I can just swap the rear tail piece with the speedo gear. If not I'll be pulling them both apart and putting the output shaft from the WJ one into the MJ 

[DirtyComanche]

I don't think cutting down the slip yoke on the driveshaft was a good idea.

[Rockfrog]

You should have had the driveshaft shortened accordingly for the new transfer case. Would have been cheaper and less hassle.

The 96+ also use a different slip yoke on the driveshaft than what any MJ ever used ... So one should have been swapped to the new driveshaft along with the associated rubber boot.

Make sure the WJ has a gear driven speed sensor on the tailshaft, they may have been Hall effect sensors and tone rings by then.

It can still be used, easier to swap the whole transfer case, but you may lose speedometer reading.

Plenty of phone apps to work around it though.

Upshot is many of the later (WJ and KJ) cases had a fat 32 spline output. Be sure to use the matching output yoke (slip yoke) as well regardless. Again, you may need to shorten the driveshaft ... Usually $40-60 balanced at a driveline shop.

[SBpunk]

I don't think cutting down the slip yoke on the driveshaft was a good idea.

Yeah don't do that hahaha

 

You should have had the driveshaft shortened accordingly for the new transfer case. Would have been cheaper and less hassle.

The 96+ also use a different slip yoke on the driveshaft than what any MJ ever used ... So one should have been swapped to the new driveshaft along with the associated rubber boot.

Make sure the WJ has a gear driven speed sensor on the tailshaft, they may have been Hall effect sensors and tone rings by then.

It can still be used, easier to swap the whole transfer case, but you may lose speedometer reading.

Plenty of phone apps to work around it though.

Upshot is many of the later (WJ and KJ) cases had a fat 32 spline output. Be sure to use the matching output yoke (slip yoke) as well regardless. Again, you may need to shorten the driveshaft ... Usually $40-60 balanced at a driveline shop.

I hadnt thought of the slip  yoke difference between the two. I have a new main shaft, chain and main shaft seal in the mail. It was more of an impatience thing. I've been working on the swap all weekend and the drive shaft was the last thing and it was about 2 inches too long. Lesson learned. I'm going to pick up a new slip yoke off ebay too if I can find the part number for the 242. I'm hoping the U-Joints were the same in the shafts. 

[DirtyComanche]

The u-joints should be the same, assuming factory driveshafts.

[gogmorgo]

My '91 MJ's driveshaft was a perfect fit when I swapped in the '93 242. As far as I know, the 231 and 242 have the same output/ds yoke, but the difference stems from the later ('96+?) sealed output style shafts vs the earlier one, so a 242 and 231 will have the same outputs, as long as both are early or both are later.

[SBpunk]

My '91 MJ's driveshaft was a perfect fit when I swapped in the '93 242. As far as I know, the 231 and 242 have the same output/ds yoke, but the difference stems from the later ('96+?) sealed output style shafts vs the earlier one, so a 242 and 231 will have the same outputs, as long as both are early or both are later.

The case I have is from a 96+ with a sealed output. Ends up being about 2 inches too long on the output and bottoms out in the yoke.

 

I picked up a new yoke Crown Automotive #4882714 for it. I'm hoping that swapping out the yoke will fix the problem and I won't have to break down the transfer case. Either way I needed a new yoke. Anyone know if its possible to run a shorter output shaft on a slip yoke or if I'm shafted and have to just crack it open and replace it?

 

[DirtyComanche]

You want the correct engagement. If too short it may pull apart otherwise, which will probably destroy your driveshaft and perhaps your fuel tank and various other things. Conversely if you push the yoke in to try to make up for that, you might bottom it and break the tcase.

 

I'd probably just order a SYE at this point.

[SBpunk]

You want the correct engagement. If too short it may pull apart otherwise, which will probably destroy your driveshaft and perhaps your fuel tank and various other things. Conversely if you push the yoke in to try to make up for that, you might bottom it and break the tcase.

 

I'd probably just order a SYE at this point.

Definitely don't want to install an SYE. Worse case I'll just crack open the case and replace the main shaft. Hopefully it won't come to that but who knows. 

[mikekaz1]

Why would you definitely not want to install a SYE that is widely seen as superior in every situation? Especially if your already removing the shaft to replace it. And already having the possibility of needing your driveshaft modified/ shortened?

 

.

[SBpunk]

There's nothing wrong with slip yoke. 4 8mm bolts and I can remove the rear DS and its never gave me any issues until I tried to put a different transferase in. Comanche long bed has plenty of drive shaft to lift it however high. Forgot to add about the cost of getting either a new driveshaft or having the old one modified. 

[DirtyComanche]

There's nothing wrong with slip yoke. 4 8mm bolts and I can remove the rear DS and its never gave me any issues until I tried to put a different transferase in. Comanche long bed has plenty of drive shaft to lift it however high. Forgot to add about the cost of getting either a new driveshaft or having the old one modified. 

 

I beg to differ.

 

However, I will admit that a SYE is largely unnecessary for a street driven rig with minimal lift and good driveshaft angles.  I was merely saying that if it was me at that point, being that his driveshaft doesn't fit, and he's already hacked the output, I'd probably just buy the flange or build the DIY one.  However, I believe Jeep ownership is the anti-economics and will regularly purchase and install 'upgrade' parts that probably are addressing issues that only reside between my own two ears.

[SBpunk]

There might be but I've just never had an issue with slip yoke. They're simple to fix and cheap. I'll have the drive shaft shortened if I have to which is what I should've done in the first place. At least now I know and I get to learn how to break down a transfer case. Sucks that I can't drive it for awhile again but still a cool thing to know. 

[SBpunk]

Just a little update. Got the 242 slip yoke in the mail but still had too much play from the tail shaft being cut. Now I'm just waiting on the shaft (hahaha) and chain to come in. Managed to get the case broken down and the stupid oil slinger was a pain. Hoping I didn't crack the tail cone but wouldn't be surprised at this point.

[Megadan]

I want to do a Tom Woods HD 242 SYE setup on the 1995 242 I just picked up that has the 32 spline output shaft.  But the cost.... Admittedly, it includes a driveshaft, but it's still a big chunk of change to lay down.
http://www.4xshaft.com/SYE/242HD.html

[SBpunk]

I'm trying to stay away from SYE / Hack and tap unless I decide to lift it more than 3 or 4 inches. LWB its not really necessary or worth the cost to me. Then again I did just drop 200+ into a transfer case because I was too impatient to get a 50$ drive shaft job done three days later....

[Megadan]

I'm staying with the slip yoke.  Just saying I would have to have the Hummer output shaft in there.  That's pretty much what it is lol.  I can't justify the $750

[SBpunk]

Exactly. That's new metric tons and axle shafts

[DirtyComanche]

IMHO, and only IMHO, the HD SYEs for the NP231/242 are a waste of money because they do not, and can not, address the front output.

 

I'd love to see the whole Hummer 242 case, it should have the 32 spline front output in it, like the NP241 does.

 

I used to cut down the hack'n'tap crowd (I still refer to them as a hack'n'crap), but I've decided that the HD rear output really isn't that likely to be worthwhile.

[Rockfrog]

Just to revisit, all the 242's I've torn apart lately have had a 32 spline front output. The 231 though still has the 26 spline front. Too bad the cases don't swap so well. Me and a buddy were looking at swapping parts about to build a stronger case. The later 242 used a 32 spline slip yoke as well but had no provisions for a speed sensor. That was the main problem in the end.

 

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[DirtyComanche]

Just to revisit, all the 242's I've torn apart lately have had a 32 spline front output. The 231 though still has the 26 spline front. Too bad the cases don't swap so well. Me and a buddy were looking at swapping parts about to build a stronger case. The later 242 used a 32 spline slip yoke as well but had no provisions for a speed sensor. That was the main problem in the end.

 

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What year ranges had a 32 spline front? The last one I pulled apart was quite old, it uses the two piece gear design like the other cases with 32 spline fronts, but I believe it was still the smaller yoke/spline setup. Unfortunately I was only opening it up for the input gear and threw the rest of it out. I don't know if I have any other ones left to look at.

 

 

WJ only for 32 spline rear then?

[Rockfrog]

I would imagine all of them, my 89 had it, and the 93 did as well. The 242 is not in the same transfer case group as the 231, they are part of the 24x family of cases, they share the same front case as the 247, 249, 241, etc... cases and parts are swappable between them. I am gathering parts to revive an old project ... The wide chain 242 ... Using 249 sprockets and chain (1.5") and a 241 planetary assembly (which also fits the 231 as the planetaries are the same for all post 87 2xx series cases).

 

The 231 uses a smaller case and the front outputs are considerably smaller. Wish it were not though.

 

The later model liberty 242 we were using also had a 32 spline output, but as mentioned, no speedo provision.

 

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[DirtyComanche]

I will stand corrected.  Apparently I never measured it, rather I just looked up the P/N for the yoke on the front output.  But the listing I used was incorrect, and showed it to be the same as the NP231.  It isn't, and in the process I tossed out a yoke that I actually could have used.

 

That WJ/KJ 242HD setup is interesting.  Unfortunately WJ/KJ parts seem to still be rather expensive, at least around here.