2WD MJ to 4WD Help me pick the trans/case

[hackedmj]

Here's what I have. An 89 MJ 2WD 4.0 auto 108k miles. I have a non disco HP 30 for the front, that's decided. The dilema is the trans and case. I have a complete trans and 231 case from an 87 with 200k miles(I've never drove). I also have a trans and 231 case from a 98 with around 100k(I've drove and know to be good). Both setups are from 4.0 engines. I would like to use the 98 stuff for the lower milage. What problems will I run into putting the newer trans/case setup into the older Jeep? Should I just use the older setup and call it good? Any opinions or advise would be great, thanks

[500 MJ]

What did the '98 trans and t-case come from?

[hackedmj]

What did the '98 trans and t-case come from?

 

The 98 drivetrain is from a 4.0 XJ. The 87 drivetrain is from a 4.0 MJ.

[Oizarod115]

the speedometer will be electric on the new case, and won't work with yours. IIRC.

 

only thing that pops into MY head

[Pete M]

Are we talking about autos or manuals here?

 

You can swap out the electric speedo thing in the t-case for the mechanical one. You might have to swap the little shafts inside them though.

 

 

[hackedmj]

All the drivetrains and vehicles are autos, What's IIRC? What about the computer in the truck for the tranny, think it'll work with the newer tranny? thanks guys.

[Oizarod115]

i think the aw4s all have the same TCU IIRC, except the ones with the power/comfort switch, but that doesnt matter.

[Pete M]

Worse comes to worst, you can just install Brett's shifter and power through the gear manually. :D

 

IIRC = If I Recall Correctly

[87manche]

all aw4's are mechanically identical. The electronics package differed through the many iterations of renix an obd.

You'll need to save the wiring harness from your trans, then graft it to the wiring harness of the new trans. a few minutes with the respective wiring diagrams should tell you what wires need to be soldered to what.

your renix TCU can control the new trans, the solenoid operation never changed.

As pete mentioned, it's not a difficult job to make the newer 231 mechanically operate the speedo. NP cases were also virualy identical, so it's as simple as removing the assembly from an older case, (88 ) and putting it into the new case (98 )