Looking for ideas for my 87

[Mjdake87]

Ok we finally got this truck in the garage and are looking for advice on what to do if it was your build.

We found this MJ in Aspen CO. 2 years ago and drove it home to northern Illinois with no problems.

Tranz went out a week later. Ok so this is what we got: 1987 comanche strait 6. / 5 speed / 4x4.

Good body almost no rust. Sun faded paint. 225k mileage. 

We pulled the tranz and found out it is the bummer peugeot BA 10/5. With NP231 T Case. Not the AX15 we hoped for.

The rear axle tag indicates a 44 3.07 L

Not sure about the front axle??

Our vision for this truck is for a 6 or 8" long arm lift but we are not crazy about cutting any fenders. This will NOT be a rock climber. Just a street legal, trail riding and some light mudding  Machine.

Looking for reasonable powerplant and tranz swap ideas and lift options. This will be a father son build and we want this to be one to remember. 

Open to anyones thoughts. THX.

 

 

[dvitha]

Well get you a ax15 with the np231 is first thing if you going to stay with the 4.0. Try and get eternal slave for it, much less hassle in the future. Front axle is most likely dana 30.

Lots of option to bump up to a stroker on 4.0.  slip yoke eliminator would be a very good option if your off-roading

 

Tire size will decide what to rear gear the front and back too. The 3.07 is a dog on trails and only good on highway with 30 or less inch tires.

3.55 would be good all around however a 4.10 would really allow you to keep that power when your about 31 inch's. I like the bfg 31's with the 4.10.

If your looking for 33 and up in size, 4.10 is minimum I think, but I would like to go deep for sure.

 

We do diff re-gearing in the shop here, make sure you take it to some one good and takes time to do. Same if you do it your self.

 

I think anyone over 32's should upgrade the brakes. put discs in the back and the upgrade master cylinder and brake booster .

 

[Dzimm]

If you want to stay with a manual then find an ax15 to swap in.  Otherwise buy an XJ that is of the same year that has an AW4 auto and swap that and all associated wiring over.  

 

If you want a big project you could look into doing an HO swap or a 97+ swap.  Basically the HO swap would upgrade you to arguably better electronics and less vacuum craziness.  A 97+ swap is even less vacuum craziness and IMO the simplest electrical system to work on due to OBD2. 

 

You already have the good rear axle but that gearing is not very good for what you want to do.  You'll want to upgrade your gears to run larger tires, 4.10 is generally the lowest you'd want to go if you are paying for a regeat but it all depends on tire size.  Your front axle will be a Dana 30 and probably have a vacuum disconnect on it.  It's a good axle but youll either want to do a one piece axle conversion or find a Dana 30 from a newer XJ as it will bolt right up and won't have a disconnect.  

 

As for the lift, any of the long arm kits will work for what you want to do and you can always build your own.  If you don't want to cut fenders, just bump stop it so the tires don't hit them.  You won't have much articulation in the axles but if you plan to primarily street drive and occasionally mud, you won't need a ton anyway.  There are some nice fender flare options that allow you to cut the fenders some for more articulation but keep a factory look.  And you can always decide after the lift how much you want to trim or not trim at all. 

[Mjdake87]

Thx for the replies. I'm fairly new to this wrenching stuff. My son has more experience in that department. But I'm good at the research. Please let me if you would do anything with these parts we have on the property.

We have: 88 2wd mj sportruck 2.5L I6. 4speed.(not sure if its AW4 or AX5) This truck runs but is very rusty. Also we have parts from a 94 xj 4.0 HO engine.

Both axles i belive are chrysler8.25 4.10 gears rear set up for SOA.

Dummy ? Is, can i use the 4.10 gears from the 8.25 and put them in the D44

Or use the xj 8.25 SOA on the Manche build.

Or regear the D44 with new gears like  Originally suggested.

 

[HOrnbrod]

1 hour ago, Mjdake87 said:

...can i use the 4.10 gears from the 8.25 and put them in the D44

Or use the xj 8.25 SOA on the Manche build.

Or regear the D44 with new gears like  Originally suggested.

 

1.  No, you can't swap gears from different manufacturers. Chrysler axles only fit Chrysler axle housings, Dana gears only fit Dana housings, etc..

2.  You can use the XJ 8.25, but you'll need to remove the XJ spring perches and weld in new perches for the MJ. They have different spacing..

 

3.  Regearing the MJ D44 is the best option I think, but re-perching the 4.10 8.25 would be cheaper. Both axles are good, but I prefer the D44's.

[Pete M]

if I had to redo my truck:

 

-HO swap from a 91-96 cherokee  (96 being OBD2) including dash and interior  (having said that, my wiring harness is a corroded pile of crap, so I need something in good shape.  if yours is corrosion free, I'd probably keep it renix and swap in an 88-90 computer which gives a few extra hp over the 87)

-95+ AX-15

-96+ np231 (has a sealed rear output)  OR any 23 spline input 231 and then rebuild it with all the goodies (wide chain, better planetary gears, and SYE)

-regear the dana 44 to 4.56 and add ZJ disk brakes 

-Tom Woods driveshafts front and rear (or at least the rear)

-dual brake booster from a WJ (one of the best mods you can do, period.)

-remove the rear height-sensing prop valve for a manually adjustable one 

-I'm assuming the front is a nice clean dana 30 and so if I was in a rust-belt state I would probably keep it (because the junkyard axles are probably in pretty sad shape) and regear to 4:56 and upgrade to late model axle shafts with the bigger ujoints and a one-piece passenger shaft. 

SOA conversion in the back 

-long arm 6" kit in the front

-armor, armor, armor.  rocker guards being at the top of my list.  I smashed both my rockers on a simple trail ride about a month before I had planned to do rocker guards.   

 

and then never, ever let it touch salt.   

 

[Dzimm]

14 hours ago, Mjdake87 said:

Thx for the replies. I'm fairly new to this wrenching stuff. My son has more experience in that department. But I'm good at the research. Please let me if you would do anything with these parts we have on the property.

We have: 88 2wd mj sportruck 2.5L I6. 4speed.(not sure if its AW4 or AX5) This truck runs but is very rusty. Also we have parts from a 94 xj 4.0 HO engine.

Both axles i belive are chrysler8.25 4.10 gears rear set up for SOA.

Dummy ? Is, can i use the 4.10 gears from the 8.25 and put them in the D44

Or use the xj 8.25 SOA on the Manche build.

Or regear the D44 with new gears like  Originally suggested.

 

Exactly what HOrnbrod said about the axles.  Most people agree that C8.25 is close to the strength of a D44 and many people, myself included, are happy running the C8.25 as it's cheap and found under many junkyard XJs.   It's super easy to install and has very good aftermarket support.  To me it doesn't make sense to seek out and pay top dollar for a D44 if you already have a C8.25 setup with a decent gearset.   

 

If the 88 mj is a stick it won't be aw4.  The aw4 is an automatic trans.