so I have an issue with my hack n tap SYE. Yes I know the issue is probably because its a hack n tap but that's how I bought the jeep. anyways, my problem is that the flange seems to be loose, even with the snap ring all the way seated and the bolt tight, its a very slight movement but once you hit around 65 you can feel it vibrating noticably. the case was freshly rebuild so I know its not the bearings or the actual shaft moving. anyone else have any similar issues with a flange type SYE? it appears to be a Rubicon Express SYE. its driven rarely right now, maybe 100 miles a month at slower speeds so should I be worried about this destroying the splines on the shaft? should I buy a new SYE kit and see if a new flange fixes it? maybe some type of shim between the snap ring and the washer?

 

I often when running into issues look first at the last thing I was screwing with.

To me since you discounted the tcase build right away. Id be inclined to look there first.

the actually bolted on yoke i have no idea about i think its not actually bolting the yoke on solid. I could be wrong since I've actually been around a jack n tap

 

I took the flange off the output shaft and there is no play at all, which is what leads me to discount the bearings. My assumption is that somehow the flange is not properly held on by the bolt and snap ring which causes it to be slightly loose. Or at least I hope it is because I dont want to buy a new transfer case output shaft because the splines are somehow worn

 

I honestly would let that 242 go for a 231. Maybe just get one for later use.
242 is for driving in on the street in 4wd good snow rig tcase. It has more going on inside it to go wrong and is expensive to do a real slip yoke eliminator. Compared to the part time 231.



I've reread your original post a few times. if you brought it to me told me the tcasd was fully rebuilt and drive line angles aren't horrible. Id say let's take it for a drive. Maybe that's the negative side of me.


Then I may notice I have no clue if this is lifted 4 or 6" or at all. Ive got no idea of u joint condition or what condition tires are in and if they're badly out of balance. It might not be tcase issues at all.

 

I have the Iron Rock Offroad Hack n tap on my np231 and it hasn't given me any issues.

 

You'd have to pry my 242s from my cold, dead hands; what an amazing piece of kit. Take a 231, make it slightly larger (and thus stronger) and add gear-driven AWD; what's not the love? The epitome of transfer case engineering before they went soft and added fluid couplers, electronics, etc.

Sounds like 1 of 4 things is at play:
Splines on shaft/yoke are worn/oversized (obviously, it needs to be tighter than that)
Hole wasn't drilled and tapped centered and "square" to the shaft (most likely)
Shaft wasn't cut off square (easy enough to do if you run the engine to spin the shaft while cutting it off)
Edge of the cut wasn't chamfered to clear the radius inside the yoke (easiest to check and fix).

The issue with H&Ts is that the splines on the stock shaft are sized for a sliding "fit", which will be slightly "smaller" than for a "fixed" fit. Technically, the Yoke could be made "oversized" to account for this; maybe they are, maybe they aren't. Ideally, there would be zero play between the yoke and the shaft and the bolt would be there solely to keep it in place (and thus any misalignment of the bolt wouldn't matter as much). Obviously that's not the case with yours. My suggestion would be to try a new yoke and inspect the edge of the cut on the shaft to make sure it's radiused/chamfered enough. Run the engine in drive to spin the shaft with the bolt sticking out a little bit (may need to use some grease to tighten it up if the thread is oversized); see if you can see any "wobble" in the bolt or on the cut surface on the end of the shaft. You may be able to fix the cut surface being out of square, but if the hole is drilled/tapped wrong, you're SOL.

The long term solution is to pick up another output shaft (I have one lying around here somewhere) and have the modification done in a lathe or get a full blown SYE. Rebuilding a 242 is pretty darn easy; just a $30 pair of a ring pliers (don't even try it without the proper type (Stanley J250G is what I used)), a small pin punch and a 2nd set of hands at one particular spot in the process (ring holding FT planetary unit to output shaft). Depending on your budget, and general plans for your XJ, the replacement shaft SYE for the 242 is pure beef; so much thicker right at the week spot on the stock shaft. If you do get into rebuilding a 242, do yourself a favor and skip the cheap kits out there; the individual bearings I ended up using were SO much smoother than those in the kit. I had previously decided to use better seals so all I really used out of the kit was a few small parts. Also, do yourself a huge favor and replace the rubber plug right next to the shift input shaft with a proper threaded plug. It wouldn't be a bad idea for anyone with a 242 to RTV theirs in as a preventative measure.

The other thing you need to check is whether it's your front driveshaft. The Front Output on the 242 sits rearward 3/8" - 1/2" compared to a 231, but they use the same driveshaft. If your XJ has aftermarket Lower Control Arms, you will probably need to lengthen the front shaft or get a new one. Getting the stock front shaft straightened, balanced and rebuilt cost me more than the aftermarket replacement did; but the shop rate was very high, you may have better luck.

 

The NP231 has proven to be stronger than the NP242, that's one of the reasons why I swapped mine out.