Auto to Manual

I love my '98 XJ, however I cannot stand automatics and I have been searching for 5 speed 97+ low mileage cherokees to replace my '98 85k mile cherokee. Then I got thinking, I've done engine swaps, transfer case swaps, why not just swap out the transmission for a AX15 or maybe the 6 speed transmission that jeep is now using. What would be needed ? I know a clutch pedal assembly, the transmission. What won't work (speedo, tach, ect...) ? Can I use my automatic cross member ? Will the output shaft have the same spline count ?

camarors8992 said:

I love my '98 XJ, however I cannot stand automatics and I have been searching for 5 speed 97+ low mileage cherokees to replace my '98 85k mile cherokee. Then I got thinking, I've done engine swaps, transfer case swaps, why not just swap out the transmission for a AX15 or maybe the 6 speed transmission that jeep is now using. What would be needed ? I know a clutch pedal assembly, the transmission. What won't work (speedo, tach, ect...) ? Can I use my automatic cross member ? Will the output shaft have the same spline count ?

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I did the opposite, I switched my ’91 XJ from a 5sp (AX15) to an AW4. Based on what I did and looking at it from the other prospective here are my thoughts:

Your current crossmember and TC should work. You'll need:
- the new trany, clutch, slave cylinder, etc....
- the hydrolics to run the clutch located in the engine compartment
- the clutch pedel
- new rear drive shaft and maybe a new front one (I believe the AW4 and AX15 are different lengths)

I pretty sure your tach reading comes from the engine and your speedo output is on the TC, so you should be good there. Your best bet it to find a wrecked XJ in a junk yard and take everything out yourself. That way you see how it all comes apart and are sure to get all the pieces.

As a side note you could probably sell your AW4 and TCU after the fact to help offset the cost of the AX15 and parts.

Good Luck

You may need a new ECM too. Although the old one may work. If the old one does work, see if you can get the extended idle to work with the 5 spd. If it does, I may just see if I can get my hands on an ECM out of an auto.

I would see if you can get an NV3550. It's a little nicer than the AX-15.

I don't think the TCU or PCM will throw any codes if you leave the TCU in place, just note connected to the tranny (it'll always think you're stopped and the engine off). On a 98 which is OBDII, removing the TCU without swapping to a manual PCM will throw a P0700 code.

The AW4 is 1" longer than the AX15. Not sure on the length of the NV3550.

You'll want to grab the xfer case shifter linkage bracket that bolts on the side of the tranny and the shifter rod that runs back to the xfer case. I'm not positive on a 98, but I found on an 89 that the AX15 the bracket sits 3" further aft and the shift rod is 3" shorter. With the tranny being 1" shorter this meant the bracket on the body side needed to be redrilled 2" further aft. Or grab the one from the donor, but you have to pull the carpet inside to unbolt it. Either way this needs to be looked at and it's much easier to redrill that bracket without the tranny in the way (btdt).

Don't forget the console trim piece around the shifter and the base plate that has the inner rubber boot.

camarors8992 said:

I love my '98 XJ, however I cannot stand automatics and I have been searching for 5 speed 97+ low mileage cherokees to replace my '98 85k mile cherokee. Then I got thinking, I've done engine swaps, transfer case swaps, why not just swap out the transmission for a AX15 or maybe the 6 speed transmission that jeep is now using. What would be needed ? I know a clutch pedal assembly, the transmission. What won't work (speedo, tach, ect...) ? Can I use my automatic cross member ? Will the output shaft have the same spline count ?

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Ok if you search around there is someplace a thread by me that covers that. I'll try to recap what I did:
Ingredients: 1 rolled manual 98 XJ, 1 in decent shape auto 97XJ.

I took the auto from the 97, dropped the manual in, had 2 wires dangling from the transmission (backup light). Also I had the harness from the auto hanging. In the auto harness, unplug it @ the firewall and identify which wire is the NSS wire and ground it (you won't be able to start without it: alternative is to run it to the clutch pedal, but I do like the ability to start in gear).

Anyways, after you have identified the NSS take the reverse light from the transmission and wire it up to the spot where you unplugged the auto harness (IIRC both wires go into that harness: I can't check till after I come back from vacation which will be early September).

Now, you have to drop the clutch pedal assembly (it's actually clutch and brake), and you have to drill a hole for the master cylinder (there is an indent that helps yo uidentify the proper location).

OK, now that you can start and get reverse lights you have another problem: after you start you will throw a check engine light. So... find ECM and pull that out along with the associated wiring as it is giving a missing tranny code and then get from a junkyard a replacement PCM (you need a manual tranny PCM as you'll be throwing a check engine light for missing ECM signal.

I think that about covers it. If I remember something else I'll post up.

Oh yeah, crossmember is identical.

XJ4playin said:

I pretty sure your tach reading comes from the engine

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Actually I think it comes from underneath the distributor