IRO Hack n' Tap SYE on a 242

89 XJ
4.0L
AW4
NP242
Rear Dana 35
RC 6.5 Long Arm lift

IRO Hack n' Tap SYE w/ drill bits and Tap
Seal Flange
Drill Jig

I was about to install my IRO Hack n" Tap today, and as I was measuring where to cut the shaft things just didn't look right.

I was planning on running my stock front DS as my rear DS but it looks way to short. without cutting the shaft on my 242 I slid the new yoke onto the TC and held my front driveshaft up into position. It looks a bit short even without cutting the shaft. It would have bolted up that way but the driveshaft was almost at its full extended length.

Instructions say to measure from the yoke to the TC shaft 33-3/4" with a picture of them measuring from the flat end of the yoke where the bolt hole is. That measurement would have me cutting a bit off my shaft.

Upon rechecking the IRO's website and the printable instructions,
I came up with 2 possible scenario's.

1) XJ Jeep Cherokee (1984-2001): 1995 model year or older require seal flange, most XJ’s with 4.5 to 8” lift height can use a front driveshaft from 1998 XJ Cherokee with automatic transmission (verify with measurement below), all other
lift heights require custom length double cardan driveshaft.

2) Certain XJ Cherokee’s will require a custom driveshaft (mostly 1989 or older, but follow the measurement
procedure in step 14 to be sure).

Is there a difference between an 89 Front DS and a 98 Front DS?

I also remember people posting about using a grand Cherokee DS a while back.

Do you have the seal flange and seal, I think you may need it.

The IRO instructions are less than perfect, I suggest you measure and cut 1" longer than your measurements and calculations. You can dry fit the yoke and shaft, and cut more of the output shaft if necessary.

Stock XJ drive shafts have different lengths depending on the options and equipment in the donor XJ, and even the exact same part number can vary 1/2 or more in length.

Yes I bought the flange and seal

I went down to ecology and picked up a 94 grand Cherokee V8 front driveshaft.
The length looks much better.
I'll mock it up and check all the measurements

Nope it was too long. looks like I have to call and order a custom one.

How much spline do you have on your output shaft? All you need is a min of 1" of spline engagement. If it will give you enough, cut it down more, cut the yoke shaft down and the ZJ shaft should work. Otherwise, send me that ZJ shaft. haha.

And here's something to check. Make sure your motor and transmission mounts are in good shape and that your engine/trans/transfer case are in the proper position. I've seen bad motor mounts and transmission mounts allow the motor to move forward up to an inch. It happened to me.