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89 comanche 2wd to 4wd swap/build thread


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Hey guys I picked up an 89 Comanche absolutely rust free, 2.5l 5 speed about a month or so ago. I have plans to swap it to 4wd and lift it at the same time, going for a 6" lift all around and 33's.

 

I have all my parts for the lift (going soa in the rear and 6" springs up front with CAD brackets. I got a 5speed transmission and transfer case from a wrecked 2000 XJ, can anybody shed some light on what issues I may run into with this swap? I know I will probably have to shorten my drive shaft, but may not have to due to the lift? And I believe I read something about a CPU not fitting correctly because of a different bolt pattern, although I'm not quite sure what the CPU is. Any help info is greatly appreciated, I'm starting the swap today. I've researched quite a bit but haven't found anything specific to what issues I may have with the 2000 trans and tcase. Thanks guys, no pics yet as this is my first post and I don't have enough post count yet.

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Trans and tcase came from a 2.5 5 speed (same as mine) just wondering if there are any issues with my Comanche clutch bolting up, I thought I heard they were different? And some wiring things, but that may just be for the aw4, I've read too much I'm getting confused

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  • 2 months later...

Well, got caught up with the swap and forgot about the build thread I had here, been posting to a local jeep page. I finished the swap and lift back the first month of August, and have been wheeling the Comanche a few times, didn't have too many issues with the swap it was pretty straight forward. First I swapped in the new front axle from a 97 TJ with 4.10s and installed the lift kit while I was at it. 6.5" lift springs, Bilstein 5100 shocks, RE CAD brackets, adjustable front track bar, stupidly I also installed a drop pitman arm which screwed up my steering angle so I still need to put the stock pitman arm back in but I'll get to that, next was the rear end, I got a rear axle from a YJ with 4.11 gearing, did the spring over axle lift, I have Bilstein 5100 rear shocks waiting to go in, but for now running stock rear shocks, I moved the rear shock mounts to on top of the axle so they are out of the way of the rocks when wheeling. Had a rear driveshaft made up because the stock 2wd one is way too long. tranny and tcase came from a 2000 XJ, 5 speed with a np231 tcase. Put some 33x12.5 BFG mud terrains on. First run offroad I damaged my front fenders because I had not trimmed or setup bumpstops so I cut the front fenders, still need to sand and paint so it doesn't rust, I want to try and mount the stock front flares on, if anyone has ideas of how to remount them I'm all ears! Made a front bumper from some Square stock I picked up. Unfortunately my motor blew this morning, I'm on a tight budget as I'm in college and can't afford to go 4.0 or v8 swap so I'm picking up another 2.5l I can't find a TBI one anywhere so I'm going to be swapping the MPI motor I'm getting over to TBI, I have an idea of what needs to be swapped to make it work but not sure if I'm thinking of everything. So far what I've gathered from various searching is that I need to swap over..

the intake, distributor, alternator and pulleys/ V belt (Z belt)? I forget what it is called, MPI has serpentine belt. Is there anything I'm forgetting?

 

*Who can tell me how to post pictures so this build thread isn't so boring?*

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So I picked up a 2.5l MPI motor from a 94? YJ, it's said to have about 72k on it. The guy gave me a bunch of spare parts he had laying around so if anybody needs a good head, pistons, rocker cover, water pump, fan, etc  PM me. Pulled my motor last night and started pulling parts off my motor to swap over. I pulled the throttle body, intake manifold, thermostat housing and clutch. Got too late so I had to head home. Going to transfer all of those parts onto the new motor tonight. It looks like my motor has a serpentine belt, I thought that people had said I would have the "V" belt but I don't, not quite sure why but I've got the serpentine belt already so no need to swap the pulleys over. Since my dummy lights never worked to begin with, I am wanting to swap my cluster over to one with gauges. I've been doing some researching and know I need to get a 90 and older cluster to work well. If it's from a 4.0 I will likely have to calibrate the tach. I'll be picking up the senders today or tomorrow and am searching for a cluster, if anybody is selling one PM me.

 

here's a couple pics from this weekends wheeling trip I went copilot with a friend

 

Nobody else in the group has an MJ, so I gotta get her back up and running so I can show them a real rig :P

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  • 1 year later...

Wow it's been a while since I was on the forum, got that 2.5 in and had some issues getting it to run... I forgot to connect a wire which caused the motor to turn over but not start. Got it running after I found the wire that wasn't connected. I ended up being convinced by my girlfriend at the time (now ex) to sell the truck. I'm never doing that again. Bought my truck back almost a year later and wheeled it all season. Well the used motor I bought proved to be not so good, it's knocking so I ordered a motor from low mileage parts, not very happy with it for the price I paid so I'm sending that motor back. I found a 1988 Comanchd 4.0 5 speed 4x4 a state away from me for $500 so I'm planning on now swapping my Comanche to 4.0 from the 2.5. I've been researching and I will be swapping just about everything over from the parts Comanche. I have three areas I'm unclear of though.

 

1. Do I need to cut my front end up to fit the radiator or can I take the front clip from the donor and bolt that in?

 

2. Since both Comanches are remix do I still have to swap interior harnesses or can I just swap the ECU and be done with it? ( planning on swapping the cluster so I can have real guages), if I do not have to swap interior harnesses will the cluster work just fine with my harness?

 

3. The fuel issue, can I just mount the 4.0 tank in my truck along with fuel pump and be done? Or is there more to it?

 

Thanks ahead for the advice guys, hoping to be more lively on here this time around. I also have a daily now so this isn't a rush but would like to finish it as quick as possible so I can get back out on the trails

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The stock tank of either truck should work.

 

I don't think that the 2.5 and 4.0 harness are the same. But ask the tech section about that.

 

Not the whole front end, just the rad support. Onlyinajeep has a post on how to do it on his 86 build

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The stock tank of either truck should work.

 

I don't think that the 2.5 and 4.0 harness are the same. But ask the tech section about that.

 

Not the whole front end, just the rad support. Onlyinajeep has a post on how to do it on his 86 build

Okay, I'll likely stick with my tank as I know it's not all rusty inside, and just swap the 4.0 fuel pump over to it. Also when you say not the whole front end, just rad support, I'm assuming I can just swap the rad support from 4.0 and not have to cut anything? Correct me if I'm wrong, I could be misunderstanding. And I'll check out that post when I get on my computer.

 

Just checked Out the Donor Comanche and it runs well, about as rusty as I expected from a New England truck but that doesn't matter for me anyways. If anyone is interested in parts that I don't use from it, let me know

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Small update, picking up the donor comanche either tomorrow or saturday. My comanche is ready to have the 2.5/tranny/tcase out. I did some research and the interior harness's should be identical because the 4.0 is also a renix motor, so I only have to swap underhood harness and ECU. The donor has a more complete/less filthy interior along with a tilt wheel so I'll end up swapping that in as well. I will post some pictures when i bring the donor home.

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Okay guys so I've pulled the motor/tranny/tcase from my Comanche, all that's left on that is to pull the underhood harness and other engine bay parts to clear it out for the 4.0.

 

Got the donor late Friday night around midnight, spent a few hours on it Sunday and disconnected the underhood harness, and almost everything else. Motor will be ready to be pulled once I finish unbolting them.

 

So just about every bolt broke when I was trying to unbolt the tranny cross member, I have bolts from my truck so not a big deal, but the AX15 cross member seems like it has extra support brackets on the upper inside frame rails, I'm assuming I have to use them? They look pretty rusty to me I don't know if they'll be useful, any advice? Also anybody think it's worth it to swap the dash and steering column just to gain a crack free dash and tilt wheel? Or would that require the inside harness being swapped as well because of the delay wipers and any other differences? Here's some pictures of the donor

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Rain coming the rest of this week, probably not going to get anything done until the weekend because of the weather but hoping to get this moving along once I have the engine bay empty to remove harness and all other things. Motor mount bolts are such a PITA a lot of the nuts have welded themselves to the bolts over the years.. Just looking forward to taking it wheeling this summer can't wait!

 

 

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So I went to do some work on my buddy's fathers truck before I worked on the Comanche and happened to split my finger wide open thanks to a bungee cord a rusty brake rotor. Left and came back in the morning to pull my motor out with my finger taped up, pulled the motor from the donor and then went and got a tetanus shot, now I'm covered for the next ten years! It's pouring out today so no work on the truck. Hoping tomorrow or Wednesday after work the rain will stop and I can get to work on the harness and whatnot. Any tips on removing the sliding glass window? I already broke one of the solid window panes trying to remove it...d3e3af874bff607bffa543119192e93e.jpg867d2fe534d74b9addfaae7fea182ec1.jpg

 

 

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Could anybody explain to me what is considered the underhood harness? Is it all of the wiring that is in the engine bay? Including wires that go into firewall, or just the big main plug that goes into fuse panel, then along drivers fender accross headlight harness to all the plugs on passenger fender? Not sure if I just need to unplug all those and they plug into my harness in my 2.5 there, going to be working on the removing harness's from both vehicles today.

 

 

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Weather is so on and off with rain and sun but I got some work done today. Pulled the harness from the donor, and the motor mounts that bolt to the chassis, also got some of the interior pulled, just about done molesting this truck then it'll go to the scrap yard. Pulled the harness out of my truck too, and started swapping over motor mounts. Probably little to no progress this weekend, I'm thinking about going up north for a weekend motorcycle cruise.

 

 

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If you're going to scrap that truck make sure you save the taillights, tailgate, the rear flares, the vents on the cab, the back interior panels, and try to cut the rear window out...  Then offer them up cheap in the for sale section if you don't need them.  They're all hard to find.

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If you're going to scrap that truck make sure you save the taillights, tailgate, the rear flares, the vents on the cab, the back interior panels, and try to cut the rear window out... Then offer them up cheap in the for sale section if you don't need them. They're all hard to find.

I've got no interest from people up in New England wanting anything unfortunately but I am going to be taking the tail lights for myself since I have a cracked driver side one, the passenger one on donor is cracked and I'm hoping to get that rear window into my truck, been wanting a sliding one for a while but I will post up the other parts for sale definitely.

 

 

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Donor harness is installed in my truck, I also replaced the Valve cover gasket and head gasket yesterday and the motor seems to be in excellent shape. My old motor... Not so much. Pulled the head off of that and the piston head is starting to break apart in cylinder 3, and in cylinder 1 and 4. Still need to remove fuel pump from the donor, apparently that won't be too fun, I'm sure by then end of sitting under it I'll be buried under a pile of rust. Better get to working on it and I'll update later on

 

 

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On pulling that pump, hose down the lock ring with WD-40 or whatever your favorite rusty lube is first, and really hose it down.  If it won't budge with a big flathead screwdriver and hammer, you can peel the tabs it locks into back with a cold chisel/screwdriver and hammer, since I'm assuming the tank is pretty much junk anyways.  Once you peel them back a bit the ring will move easily with the same screwdriver and hammer.  Get a new lock ring for when you swap it over to your tank, and put the lock ring in with grease on it so it will slide in easily and not get seized for next time.  Should be a 5 or 10 minute job under the truck...

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Took both fuel pumps out, put my dash in, and got motor in myself, what a PITA that was doing it with tranny and tcase attached. Now it should go smoothly from here. Picking up a new fuel pump tomorrow or Tuesday, going to rain until Wednesday but hoping it stops a little so I can get some work in.

 

 

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Anybody have tips on removing rear window? Trying to take out the sliding glass window so I can put it in my truck. Broke one of the solid panes thinking I had gotten through the seal but I guess not. I did remove the gasket already

 

 

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