Permutations and combinations

[Eagle]

As my signature indicates (I think), one of the MJs I currently own is a 1988 2WD SporTruck 2.5L 4-speed. It has been off the road for a long time because it blew the clutch slave cylinder and had too much else on my plate to repair it. The body seems to be basically sound -- haven't crawled underneath to fully assess the condition underneath, but I expect it to be salvageable. I'd like to put it back on the road and do some upgrades, but I'm severely conflicted over what direction to take regarding power train. Which way would you go ... and why? My options are:

1. Replace the clutch and slave cylinder and keep it as a 2WD 4-speed.
2. I have a complete AX-5 and transfer case from an '88 2.5L, so I could replace the clutch, and swap the tranny and transfer case to make it 4WD.
3. I have all the parts, including the bell housing, to convert the 2.5L to an AW4. That would go 4WD.
4. I also have a complete '87 XJ 4.0L 4WD AW4 drive train, so I could convert to a complete 4.0L automatic setup.

It's currently sitting on a 3.54 rear axle. I have a couple of 3.54 front axles, I have front and rear MJ axles in 3.73, and I have an '86 XJ 2.5L sitting on 4.10 axles.

 

What would you do?

[HOrnbrod]

"The body seems to be basically sound -- haven't crawled underneath to fully assess the condition underneath, but I expect it to be salvageable."

 

^^^^ Nothing until i did this. ^^^^

[fiatslug87]

It depends how you plan on using it. If the frame is in good shape I would go the 4.0L, AW4, 4.10 route.

[Manche757]

I assume you have checked the frame and found it in good order.  4.0L   5 speed   2WD.  If you are "saving" a MJ, are you expecting to run it in the surf on a salt water beach?  On salt covered winter roads?  Hopefully it will be parked then, even if not in a garage.  Sell the 4WD to one of the chopemup young guys.  You will end up with a better truck. Clear the garage a little and make a buck.  

[omega_rugal]

replace the slave... keep it 2 wd 4 speed... or you have so much free time? if so, go for the 4.0+aw4+4wd+3.73 axles

[Wounded_Fighter]

On 8/24/2018 at 10:57 PM, Eagle said:

haven't crawled underneath to fully assess the condition underneath, but I expect it to be salvageable.  

 

This is where I'd start.

[HOrnbrod]

[MeanLemons]

If you do the 4cyl with the aw4. I think none of the axles you have would be a good combo, considering (I believe) that the factory ratio for 4cyl/auto would be 4.56.

 

i have seen a couple of XJs with that combo & ratio.

 

so that leaves the option of 4.0L drivetrain with 4.10 gears if you plan on running 31’s

 

if you plan on keeping stock tires, but plan on hauling a lot of loads... do 3.73’s

 

otherwise do the 4 cyl with ax5 & 4.10

[Eagle]

14 hours ago, MeanLemons said:

If you do the 4cyl with the aw4. I think none of the axles you have would be a good combo, considering (I believe) that the factory ratio for 4cyl/auto would be 4.56.

 

i have seen a couple of XJs with that combo & ratio.

 

 

The XJs with 4 cyl and 4.56 were using the 904 3-speed tranny, not the AW4 with overdrive. Now that I think about it, I have no idea what ratio the factory used with the 2.5L and AW4 combinatuion.

 

[MeanLemons]

1 minute ago, Eagle said:

 

The XJs with 4 cyl and 4.56 were using the 904 3-speed tranny, not the AW4 with overdrive.

I was told they were aw4’s.  I think cruiser was the one who told me.   Interesting though 

[MeanLemons]

25 minutes ago, Eagle said:

 

The XJs with 4 cyl and 4.56 were using the 904 3-speed tranny, not the AW4 with overdrive. Now that I think about it, I have no idea what ratio the factory used with the 2.5L and AW4 combinatuion.

 

I still would say it’s 4.56... 

 

the way i look at it.

 

4.0L with AX15.... 3.07

4.0L with AW4..... 3.55

2.5L with AX5....   4.10

2.5L with AX4.....  3.55

 

 

It would stand to reason that it would be 4.56.