I bought a 242 today for $100. Guy claims its from a 94 xj, but the tag on it shows it was built in 1991
So I can be confident the two have different gear cuts
I measured the input shaft length on the 242, and I'm getting ~.60" or so measuring it like this:
So my first question, am I measuring this right? If not, where am I supposed to measure to? All I can find is that there's a .75", .84" and 1.5" input shaft lengths, so I dunno what I have here.
Second question, assuming that I do have the .840" input shaft in my truck now, can I still use this one, or do I NEED the full .840" input shaft (can I use the shorter one, in other words?)
And third question, if I do need to switch the input shafts, being that I have two cases with different gear cuts, I should be able to use the front half and the shaft from my 249 and afix it into the 242 to make it work, correct?
Thanks in advance!
After a bit more reading it looks like I WILL have to change shafts, and in doing so it's going to be a pain because I have two different gear cuts. Now am I right in reading that I can change the input and planetary from the 249 into the 242 and be fine? Or will I have to swap the front case half as well? If so, is there any write up's on whats involved with that?
Your ZJ does indeed have the .840" input shaft.
I'm not sure how to measure it. I believe it is measured with the seal retainer off, but don't quote me on that. Either way, you should have the .750" input on the 242. 91-95ish with the AW4 used the .750" input.
You read correctly. You'll definitely have to swap the gears. In fact, you'll have to use the front case and the input/planetary from the 249 and several other things from it to do this swap.
You will have to drill a hole for the shift rail roll pin as well as drill and tap a hole in the front case to get to it. The 249 does not have either hole.
The front case attaches to the Jeep. The rear case has the rear output coming out of it.
I'll give you an overview of what you will need to use.
Front Case - 249
Seal Retainer - 249/242
Input Gear and Planetary - 249 - Is held together with snap rings. Can't miss it
Shift Rail - 242
Mode and Range Forks - 242
Front Output Gear and Yoke - 249/242
Rear Case and Extension Housing - 242
Speedometer Sensor and Gear - 249 - Make sure to take note of the markings on the housing to get things in the proper place. Failure to do so can result in a broken speedometer gear.
Mode Sensor - 249, however you will get incorrect readings. If the VIC connectors are swapped inside the Jeep, the sensor will read Full-Time when the case is locked 50/50. Don't drive on pavement with that lit up. Easy.
Shift sector plate - 242 - The linkage on the outside of the case attaches to this.
You'll want to put new range/mode forks (EDIT: pads not the forks!! the little plastic pieces that are on the forks. You can't miss them.) on the 242 as well as do all bearings and seals. Don't quote me on the seal retainer though. That could go either way. If something doesn't work, you'll immediately be able to try the other one. If it works, great.
Good luck with the swap.