Taddraughn's 1989 Comanche Progress Thread

[89 MJ]

On 8/9/2025 at 1:15 PM, taddraughn said:

Is it worth swapping over to an AX15?

I think that this really depends on how you plan on using the truck. If the truck is going to stay stock and see minimal towing or hauling heavy loads, I think that the Peugeot will be fine. Now if you're a person that likes dumping the clutch on occasion or getting rubber when you shift or you plan on towing and hauling a lot with the truck, I'd swap to an AX-15. 

 

Having put a few thousand miles on both transmissions, I can tell you that the Peugeot feels like a car transmission and that the AX-15 feels like a truck transmission. The Peugeot is very smooth and I think it would be very fun in a weekend cruiser type of truck. I also don't think that I've ever heard of anyone blowing up a Peugeot either. I've heard they're weak, but in my years here, I don't recall seeing anyone post that they actually blew the trans up. The AX-15 is comparatively not very smooth. You cannot shift it quickly at all when its cold and it still is not a transmission that wants to be shifted quickly when it gets up to temp. All three of my AX-15 MJs were like this. That said, my truck is on bigger tires, has deeper gears, and a larger rear axle than stuck, plus it tows and hauls on occasion, so the AX-15 was the right way for me to go and I would do it again.

 

Another thing to consider is the long term value. If you fix the truck and then decide to sell it down the road, I think keeping the Peugeot will actually hurt the value, even though it is the factory transmission. The AX-15, especially an external slave AX-15, will add value to the truck. 

 

Now if you do decide to swap in an AX-15, now is the time. I think its far easier to have the transmission connected to the engine and swing them in together than it is to pull the transmission under the truck. Keep in mind, the AX-15 had a different crossmember and the XJ and MJ AX-15s had difference transfer case clocking than the YJ and TJ ones. I believe that the external slave AX-15 came out in 1994 and that is the one that you really want. The new internal slave cylinders are prone to failure. 

[taddraughn]

On 8/11/2025 at 5:16 PM, 89 MJ said:

I think that this really depends on how you plan on using the truck. If the truck is going to stay stock and see minimal towing or hauling heavy loads, I think that the Peugeot will be fine. Now if you're a person that likes dumping the clutch on occasion or getting rubber when you shift or you plan on towing and hauling a lot with the truck, I'd swap to an AX-15. 

 

Having put a few thousand miles on both transmissions, I can tell you that the Peugeot feels like a car transmission and that the AX-15 feels like a truck transmission. The Peugeot is very smooth and I think it would be very fun in a weekend cruiser type of truck. I also don't think that I've ever heard of anyone blowing up a Peugeot either. I've heard they're weak, but in my years here, I don't recall seeing anyone post that they actually blew the trans up. The AX-15 is comparatively not very smooth. You cannot shift it quickly at all when its cold and it still is not a transmission that wants to be shifted quickly when it gets up to temp. All three of my AX-15 MJs were like this. That said, my truck is on bigger tires, has deeper gears, and a larger rear axle than stuck, plus it tows and hauls on occasion, so the AX-15 was the right way for me to go and I would do it again.

 

Another thing to consider is the long term value. If you fix the truck and then decide to sell it down the road, I think keeping the Peugeot will actually hurt the value, even though it is the factory transmission. The AX-15, especially an external slave AX-15, will add value to the truck. 

 

Now if you do decide to swap in an AX-15, now is the time. I think its far easier to have the transmission connected to the engine and swing them in together than it is to pull the transmission under the truck. Keep in mind, the AX-15 had a different crossmember and the XJ and MJ AX-15s had difference transfer case clocking than the YJ and TJ ones. I believe that the external slave AX-15 came out in 1994 and that is the one that you really want. The new internal slave cylinders are prone to failure. 

 

Thanks for your input. Leaning towards just going ahead with the AX15 swap as long as I can find the correct crossmember somewhere

[taddraughn]

Got back from my work trip and tore the engine apart yesterday. 

 

#6 appears to have been running hot or lean maybe... That was the cylinder that I think maybe wasn't firing when I ran it briefly to move the truck. Spark plug looked brand new when I removed it.

 

 

Anyway, pulled the pistons out. Pretty good ridge at the top, but pistons are original size, so should be no problem to get it to clean up. I do have a cheap bore gauge but figured I'll just take it to the machine shop and let them tell me how much it needs to clean up/what pistons to order. 

 

 

The block was so filthy I decided just to pressure wash it. Normally wouldn't spray a bunch of water on a raw cast iron block but dried it off immediately and then used about 1.5 cans of WD40 on it before blowing it off again and wiping it with WD. With the core plugs out I was able to clean up the water jackets really well. Got a lot of rusty bits out of there.. Machine shop can clean it up the rest of the way. Interestingly I found some a letter by each cylinder. Not sure if this is something the factory did for some reason related to the bore size? 

 

 

Anyway.. block is loaded up in my wife's Crosstrek and ready to go to the machine shop. 

 

 

Crank looks okay, but probably could use a polish. Need to mic it and see if it's still in spec or would still be in spec after a polish. If it needs grinding I'll probably just buy a new crank as it might be cheaper than having it ground. 

 

Cam looks meh.. has a chip in the first lobe that I don't like. Was thinking about switching to a hydraulic roller cam that newcomer is offering but with all the stuff you need to make it work it gets expensive... 

 

 

[taddraughn]

Dropped off the block and rods/pistons at the machine shop. They said "give us a couple days" lol. 

 

So who knows I may be getting this engine back together in the next couple weeks. I thought about stroking it but decided just to keep it stock and go with Sealed Power replacement pistons for whatever oversize the shop determines is necessary. 

 

Will measure the crank this week and see if I could polish it and use .001 bearings to make up the difference. 

 

Not sure yet what I'll do with the head and cam. Thinking about just getting an edelbrock head for it or maybe a rebuilt one from clearwater.

[taddraughn]

Block is back from the machine shop. Got sealed power pistons in .040 over size assembled on my rods and some hastings rings I need to gap and install. 

 

Ordered a bunch of stuff from cleggs including an edelbrock performer head, banks exhaust, and some ARP hardware. 

 

Will take some photos as I prep and paint the block, get the new expansion plugs in, etc. 

[taddraughn]

Got some paint on the engine block.

 

 

 

Also started to strip the engine bay so I can clean it up

 

 

 

I'm thinking about having the truck painted or paint it myself despite my hatred of bodywork. If there's anything I hate more than bodywork it's maybe only paying someone to do something I'm capable of doing myself.

[Gojira94]

Looking good! No moss growing on this project... 

[Gojira94]

On 8/22/2025 at 1:06 PM, taddraughn said:

Ordered a bunch of stuff from cleggs including an edelbrock performer head, banks exhaust, and some ARP hardware. 

 

 

I admit I'd love to have one of those just to see how much of a difference it makes. It would fit my setup since I've HO swapped, but I'd have to go back to a log-style intake. What's your plan, since you're starting with an all-Renix setup?

 

This cylinder head is machined to accept both distributor or coil pack ignition. To optimize airflow, this cylinder head is designed with a 1991-2006 4.0L intake port location and 1991-98 4.0L exhaust port size. As a result, this cylinder head must be used with a 1991-2006 intake manifold and a 1991-1998 exhaust manifold. Aftermarket exhaust headers can also be used in place of 1991-1998 exhaust manifolds and MUST be used in place of 1999-2006 exhaust manifolds. Most aftermarket exhaust headers are compatible, but please check with the exhaust header manufacture to verify. This head is NOT compatible with 1999-2006 OEM exhaust manifolds.

 

This thread might help you consider options:

 

 

[89 MJ]

6 minutes ago, Gojira94 said:

As a result, this cylinder head must be used with a 1991-2006 intake manifold and a 1991-1998 exhaust manifold.

I find this hard to believe. This must just be giving Edelbrock plausible deniability. I have a Renix intake on a 0630 HO head and it didn't require any modifications other than slight grinding to get it to clear the HO exhaust manifold. As long as a Renix intake gasket is used, it should be alright. 

[Eagle_SX4]

2 hours ago, Gojira94 said:

 

I admit I'd love to have one of those just to see how much of a difference it makes. It would fit my setup since I've HO swapped, but I'd have to go back to a log-style intake. What's your plan, since you're starting with an all-Renix setup?

 

This cylinder head is machined to accept both distributor or coil pack ignition. To optimize airflow, this cylinder head is designed with a 1991-2006 4.0L intake port location and 1991-98 4.0L exhaust port size. As a result, this cylinder head must be used with a 1991-2006 intake manifold and a 1991-1998 exhaust manifold. Aftermarket exhaust headers can also be used in place of 1991-1998 exhaust manifolds and MUST be used in place of 1999-2006 exhaust manifolds. Most aftermarket exhaust headers are compatible, but please check with the exhaust header manufacture to verify. This head is NOT compatible with 1999-2006 OEM exhaust manifolds.

 

This thread might help you consider options:

 

 

You can use any intake manifold (horseshoe or log style) on the Edelbrock head but you can't use the 2 piece cast iron exhaust manifolds on them. 

[taddraughn]

Thanks for the info guys. 

 

I had seen they claimed it was only compatible with the certain year intakes. I figure I'm good with the banks exhaust since they claim any aftermarket exhaust will work. 

 

For the intake I'll see how my Renix one fits up. If for any reason that won't work I was just planning to use the later year intake they claim is required and then adapt the throttle body to the later intake somehow as seems like that changed and I assume I need to keep the TB if i'm sticking with the Renix ECU? 

 

As for the exhaust I was thinking about just running a wideband and then using my REM to convert to narrowband and feed that to the ECU.

[taddraughn]

 

Was feeling like Christmas until I opened the box the crank was in.. 

 

 

 

Guy at Cleggs was super fast to respond and is going to check on the stock he has to see if the others look the same or are better. Really would have expected these to be coated in a wax or something but this one is definitely just bare. I could chuck it up in my lathe and polish it, but I paid for one in good condition... 

[taddraughn]

Just a little update about the crank. Cleggs is working with me to swap it for another. Really happy with their customer service and how quickly they're rectifying this for me.

 

Should be able to get the piston rings gapped this weekend and that'll be about all I'm able to do while I wait on the new crank to come in.

 

 

[taddraughn]

 

Engine bay almost all the way stripped down now. After a just a little de greasing I found there is some color under there lol!

 

Also have the interior almost completely stripped now too save for one of the seatbelt bolts that someone stripped out. 

 

 

 

I'm actually starting to lean towards just buying an XJ so that I can swap in the interior and heater box etc. from a 97+. 

 

Thinking the advantages here are having a good R134A AC system, OBD2, and more modern interior. So much of my interior is completely shot I'm pretty sure it's cheaper just to buy an entire XJ than piece it together with good used parts from ebay. Like just a set of seats on ebay is 500+ dollars.. 

 

I wasn't really itching to get away from Renix, but a wholesale swap seems like the only way to go. Most cars around are auto though.. would much rather find one that's already a manual so it's basically got everything I need for the Comanche. Although I could probably make this work swapping the interior and harness from an auto car and then just sourcing the manual separately. Let me know what you guys think or if you have any leads a manual 97+ that has a good condition interior 

[Gojira94]

Last 2 pics bringing back the memories on my project. Your floors are way better at least. Seems like you have all the skills and equipment to do the 97+ swap. No judgement from me if you go that route. I only went halfway and did HO on Renix. My HOA would not have stood for me cutting up a junk XJ in my driveway or back yard. 

[89 MJ]

Make sure you read through some threads on the full 97 swap first. I know the pedals are difference and the steering column hole of the firewall area needs to be changed. Honestly, with the REM, I think that Renix is just as reliable as an OBDII Jeep. Even the later XJs are still becoming old cars at this point, so before long, I suspect that they will have similar issues that Renix is known for.