Drivetrain Swap Advise?

[dcramer67]

Hey everybody! I am new to this forum so please bear with me, but I have a question I think you guys can answer.

So, I have been looking for a comanche or cherokee to buy and build for awhile now.  The other day, I came across and bought this off of craigslist...

It is a '96 Cherokee that had been sitting for 2 years untouched.  The body is almost completely rust free, and the underneath is in surprisingly good shape as well.  It only has 103K miles on it and I went to jump start the thing and it fired right up, and I could drive it right out of there.  The interior is also near mint.  The problem is that the I bought it off an older lady who has her name and her ex-husbands name on the title.  Her husband up and left a few years ago, and is nowhere to be found.  I live in PA, so it is almost impossible to transfer the title without his notarized signature, but I thought this could make a really nice donor jeep if I found another xj or hopefully an MJ.

 

Now I have the oppurtunity to buy this...

It is an 87 MJ that has 187K miles on it.  It has a 5.5" long arm kit on the front and is SOA in the rear.  The problems with this are the floor boards are rusted out pretty bad but from what I understand that is normal.  Also, the current owner says the transfer case needs rebuilt or replaced, and the rear driveshaft broke off and he lost it the last time he was wheeling it.  So right now, it would need towed to my house or driven in front wheel drive which is risky when the owner says the transfer case is going out.

 

Anyway...how difficult would it be to take the engine, tranny, tcase, everything from the cherokee and put it into the older style comanche?

 

Here are more pictures of the two jeeps because why not?

Cherokee Front interior

Comanche front interior

Comanche passenger side floor board

Comanche dented hood

Comanche bed

No driveshaft

Dented up bed...this thing was obviosly wheeled

Comanche driver side floorboard plugged with JB Weld

[87MJTIM]

You did not mention what engines are in each Jeep.  I will assume both are 4.0.  If the MJ runs fine, you could swap over the trans and tcase from the XJ.  You will need to get a new rear drive shaft.  The MJ will need a longer one than the XJ has.  After that you maybe good to go.

 

I say you should swap BOTH the trans and tcase because the output/input shaft spline counts changed.  The 87 trans may not fit up with the 96 tcase.

 

If you want to do a complete engine/drivetrain swap, that is more involved.  You will need to take everything out of the XJ and put it into the MJ: engine, wiring both engine bay and interior, and swap over the dash as well.

 

Nice find on both Jeeps.  The MJ floors don't look as bad as mine did.

[dcramer67]

You did not mention what engines are in each Jeep.  I will assume both are 4.0.  If the MJ runs fine, you could swap over the trans and tcase from the XJ.  You will need to get a new rear drive shaft.  The MJ will need a longer one than the XJ has.  After that you maybe good to go.

 

I say you should swap BOTH the trans and tcase because the output/input shaft spline counts changed.  The 87 trans may not fit up with the 96 tcase.

 

If you want to do a complete engine/drivetrain swap, that is more involved.  You will need to take everything out of the XJ and put it into the MJ: engine, wiring both engine bay and interior, and swap over the dash as well.

 

Nice find on both Jeeps.  The MJ floors don't look as bad as mine did.

 

 

Thanks.  How hard would it be to swap out the dash, all the electronics, and the wiring?  I imagine it wouldn't be that hard because you would know where everything goes taking it off the XJ.

[87MJTIM]

There are a few write ups on doing HO swaps.  You will have to research for it.  I have not done it.

 

What I have read, though, it that the electronics are completely diff from Renix to HO.  So a complete interior swap may have to be done.

[MrSimon]

You don't have to swap out the interior/dash/gauges.  You can if you want to, but it's not necessary.  I put a 99 XJ motor/Trans/TC into my 87 MJ and didn't touch the interior.  You have to get creative with the wiring harness though, and you need to add in a few relays here and there and swap out a few sensors.  Personally, I liked the original interior of the truck and didn't want to change it.

[dcramer67]

You don't have to swap out the interior/dash/gauges.  You can if you want to, but it's not necessary.  I put a 99 XJ motor/Trans/TC into my 87 MJ and didn't touch the interior.  You have to get creative with the wiring harness though, and you need to add in a few relays here and there and swap out a few sensors.  Personally, I liked the original interior of the truck and didn't want to change it.

 

So really I could go either way with the interior.  The xj I picked up has super nice interior which is why I was leaning that way, but having to run all of the wires seems like a real PITA.  At least now I know that it is possible to do it either way.  Thanks!

[MrSimon]

 

You don't have to swap out the interior/dash/gauges.  You can if you want to, but it's not necessary.  I put a 99 XJ motor/Trans/TC into my 87 MJ and didn't touch the interior.  You have to get creative with the wiring harness though, and you need to add in a few relays here and there and swap out a few sensors.  Personally, I liked the original interior of the truck and didn't want to change it.

 

So really I could go either way with the interior.  The xj I picked up has super nice interior which is why I was leaning that way, but having to run all of the wires seems like a real PITA.  At least now I know that it is possible to do it either way.  Thanks!

 

Just to be clear, it probably is easier to just swap everything over, including the dash, gauges etc ..... but you don't HAVE to.