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Old March 27th, 2017, 23:41
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yellowoctupus yellowoctupus is offline
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1998 AW4 2WD to 1991 AX15 4WD Swap

So I'm diggin', diggin', diggin', to try to reduce surprises as I go down the path of making my wife's DD 1998 2wd auto a 5sp 4wd. The object of this swap is to still retain DD 'stock' like Jeep, not making a wheeler at all. I have a '55 Willys for wheelin' already. Here's what I've got so far:

1998 Cherokee 2wd AW4- Rear Dana 35 (swapped in due to a dead 8.25 years ago)
1992 Cherokee 4wd AW4- Axle Donor, Rear 8.25, Front Dana 30
1991 Cherokee 4wd AX15- Trans, driveshafts, pedals etc donor

So, I think I should have most of the 'large items', trans, pedals, tc, driveshafts, axles, etc, but I'm sure it's going to be the 'little things' that kill me when I'm doing this swap.

I did the internal to external slave swap a few years ago on a (sold) 91 Comanche I had, and was very happy with the results, but I ran across this, which I could find nothing else about!:

"Also, some people adapt Jeep Iron Duke four-banger or '75 Land Cruiser external slave cylinders to the early AX15 bellhousings."

From: http://www.fourwheeler.com/how-to/tr...ion-swap-jeep/

Questions:

1. Anyone know what the above mentioned Iron Duke external/internal swap is all about? If it's reasonable to do, I'm all in. Internal slaves suck! (although the 91's right now feels good...)

2. Can I swap out the complete pedal hanger from the '91 into my '98, or are there firewall/steering column differences?

3. Do all of the crankshafts have the same diameter pilot? Ie, can I just purchase a pilot bearing for a '91 and expect it to fit the crankshaft AND the input shaft?

4a. Regarding the ECU, for a 98, can I jumper a few wires in the harness to the ECU to make it think it's in Park or Neutral? I read about doing this for a 91, but I know there are vast differences between 91 and 98 regarding ECU to TCU and Transmission communications. If not, how can I identify a manual ECU that will work for our truck? (98-01, 96-01 OBDII cutoffs etc?)

4b. If I run the auto ECU, will it go into some BS 'limp home' mode if it has no / incorrect signals from the trans/TCU, or will I just get the CEL with no other reduced drivability?

5. Regarding flywheels, I read that you must get the correct YEAR flywheel to get the CPS to read properly. Omix Ada's PN on Rockauto shows the same flywheel for 1991-1999 XJ's. What's the scoop?

6. Seeing as my donor axle vehicle is an auto, I'm ASSUMING it has the 3.55 gears, where it is probably supposed to have 3.07 gears for the 5sp. Can I just reuse the speed sensor from the 98's auto transmission to get the speedo to work properly?

7. Cruise control... will it work properly right away? I'm guessing it should have at least a clutch safety switch as well as a brake safety switch to 'cancel' it when either is depressed. Anything else?

8.
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Old April 1st, 2017, 02:36
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yellowoctupus yellowoctupus is offline
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Re: 1998 AW4 2WD to 1991 AX15 4WD Swap

Well, since nobody else is jumping in......

3. From Novak Adapter's Website, and they warn these cutoffs are approximate:

1991 and earlier crankshafts, 1-1/16" Pilot OD
1992+ crankshafts, 1" Pilot OD

AX15 Early, 1988 to 1991 at ~19/32" diameter
AX15 Late, ~1992+ at ~3/4 diameter

Easy to find bearings for each combo except mine (98 Engine, 91 Trans).

0.594 ID 1.0625 OD National FC66426
0.594 ID 1.0 OD Novak PN ONLY?? 2001295
0.75 ID 1.0 OD National S-128, SCE1211, SCE1295
0.75 ID 1.0625 OD National PB7HD (72 Wagoneer 4.2, 304etc ferinstnance)

Really cool search feature here for National's Parts: Search for Needle or Clutch Pilot

4a. ECU needs to be a manual for idle/stalling issues besides CEL illumintaion regardless of solenoid sensing due to speed sensor issues etc etc. ECU can be reflashed, about $40+shipping.

8. Searching Autozone's website, they list for the 98 Cherokee a pilot that is .7518"ID, 1.8161"OD. Is this supposed to be flywheel mounted or something???
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Old April 16th, 2017, 22:54
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yellowoctupus yellowoctupus is offline
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Re: 1998 AW4 2WD to 1991 AX15 4WD Swap

Answers:

2. Early and Late model pedals (96/97 changeover) are not interchangable. Mounting points are a bit difference under the dash. Not sure if firewall/brake booster to clutch holes are the same, but the top of the pedal bracket is quite a bit different.
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Old April 18th, 2017, 12:17
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themauler themauler is offline
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1998 AW4 2WD to 1991 AX15 4WD Swap

I will chime in. I took a 97 ax15 and put it in my 93 xj a few years ago. Pedals from the newer body style will not fit. (Confirmed)

Clutch safety switch is dumb. Plus sometimes you want to start in gear (4lo).

Cruise control will work fine if you can trick the ECU/TCU that you are in Drive.

I have had both the external and internal slave and actually prefer the internal slave. Impossible to bend a clutch fork this way.

I used a 97 flywheel on my 93xj. Works fine.

My 93 didn't go into any sort of limp mode. Jeep ran just fine. Just save your speed sensor from the 92 as the sensor type is different from the 98. That's all I can think of at the moment.


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Old April 18th, 2017, 22:54
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yellowoctupus yellowoctupus is offline
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Re: 1998 AW4 2WD to 1991 AX15 4WD Swap

Hey, thanks for the input! It appears to be a little easier to go from newer to older, like you did. I actually threw my '91 parts truck back together to sell; at this point I'm hoping to find a complete '97+donor instead of cannibalizing a complete running driving truck (the 91). Will keep y'all posted on what I end up doing. So far I swapped in the manual 4wd axles (3.07) in preparation for the transmission swap and that's about it.
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Old June 4th, 2017, 23:23
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yellowoctupus yellowoctupus is offline
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Re: 1998 AW4 2WD to 1991 AX15 4WD Swap

Well....my plans changed a little. I picked up a wrecked 98 4.0 5sp and am going to use everything I can out of that. Feels a little like cheating, but damn it's easier than trying to make the square peg fit in the round hole for once in my life. Got it super cheap too, thankfully, but now I'm up to my ears in Cherokee parts!
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