42RLE in a 2000

[mjonesjr84]

One of my winter projects for the Jeep is to convert it to an automatic transmission. I never drive my Jeep where it would need overdrive so I've always thought a 32RH would be what I put in. However, I have an opportunity to buy a 2004 Rubicon for $5k that has the 42RLE. My thoughts were to swap the transmission & transfer case so I would also get the 4:1 benefit from it and part out the rest fo the TJ. Around here I could almost get my month back on just the Rubicon axles. I'd also thought about swapping my axles and interior goodies (seats, cage, etc) over to the Rubicon, but the tub has some rust.

So I have a couple of questions for the more experienced ones.
1. Should I keep looking for a donor Wrangler with a 32RH?
2. Is the 42RLE really that bad off road?
3. Would I have to swap all the wiring from the 2004 to my 2000 for it to work?

 

[jjvw]

...
2. Is the 42RLE really that bad off road?

What bad is being said about the 42 in an off road context? It is a hot transmission and quite likely benefits from an auxiliary cooler. This is true both on and off road.

3. Would I have to swap all the wiring from the 2004 to my 2000 for it to work?

You will need to run the 2004 PCM and the entire matching dash harness in the 2000. You will end up converting your 2000 into a 2004.

 

[mjonesjr84]

What bad is being said about the 42 in an off road context? It is a hot transmission and quite likely benefits from an auxiliary cooler. This is true both on and off road.



You will need to run the 2004 PCM and the entire matching dash harness in the 2000. You will end up converting your 2000 into a 2004.

From what I've read, heat is why it was unliked over the 32RH. I'd planned on running a big cooler with auxiliary an auxiliary fan on it no matter the transmission.

So basically doing a full interior swap to the '04. Not sure I'm into that much work.

 

[jjvw]

From what I've read, heat is why it was unliked over the 32RH. I'd planned on running a big cooler with auxiliary an auxiliary fan on it no matter the transmission.

So basically doing a full interior swap to the '04. Not sure I'm into that much work.

We have changed two late TJs from manual to the 42rle, swapping year to same year. It is a very invasive project. I can't imagine trying to make an early TJ run the 42.

 

[mjonesjr84]

We have changed two late TJs from manual to the 42rle, swapping year to same year. It is a very invasive project. I can't imagine trying to make an early TJ run the 42.

I've done a few manual to auto swaps and they are a big job. Thanks for the info!

 

[JMT]

From what I've read, heat is why it was unliked over the 32RH. I'd planned on running a big cooler with auxiliary an auxiliary fan on it no matter the transmission.

So basically doing a full interior swap to the '04. Not sure I'm into that much work.

Heat and the 0.69 OD ratio.

You need the OD switch on the dash harness.

 

[AndyG]

Blaine knows a tons of swap details-

You can make the 42 turn the OD off automatically when you put it in gear each time with a relay.

@Jamison C put one in a later model. Amazed me to see it done.

 

[mrblaine]

Blaine knows a tons of swap details-

I do and I've been pondering this one. I still don't have a clear path to max result with least effort yet.

You can make the 42 turn the OD off automatically when you put it in gear each time with a relay.

Only useful if you lost your right hand forefinger in a terrible construction or nose picking accident. Otherwise, just extend the fucking thing when you grab the shifter to take it out of park. It hits exactly at the OD off switch.

@Jamison C put one in a later model. Amazed me to see it done.

Put one what?

 

[AndyG]

I do and I've been pondering this one. I still don't have a clear path to max result with least effort yet.

Only useful if you lost your right hand forefinger in a terrible construction or nose picking accident. Otherwise, just extend the fucking thing when you grab the shifter to take it out of park. It hits exactly at the OD off switch.

Put one what?

A 42 auto in a manual rig- think it was all ‘04 stuff -

 

[mrblaine]

I've done a few manual to auto swaps and they are a big job. Thanks for the info!

The dash harness to get the OD off switch has got me hung up until I think through it. A lot of the 03-04 manual to auto conversions we've done have the OD off connector just stuck in the back of the switch blank so it is as simple as adding the switch.

I'm almost certain to do that in a 2000 would require moving all the harnesses over and converting it to an 04 and we are dealing with 2 different busses plus the emissions moving from under the hood to the rear tail light area.

What shape is the frame in on the 04?

 

[mjonesjr84]

The dash harness to get the OD off switch has got me hung up until I think through it. A lot of the 03-04 manual to auto conversions we've done have the OD off connector just stuck in the back of the switch blank so it is as simple as adding the switch.

I'm almost certain to do that in a 2000 would require moving all the harnesses over and converting it to an 04 and we are dealing with 2 different busses plus the emissions moving from under the hood to the rear tail light area.

What shape is the frame in on the 04?

The tub and frame are worthless as they are rusted. I was just going to use it for the auto swap and 4:1 transfer case, then sell the axles to get most of the money back out of it.

 

[mrblaine]

The tub and frame are worthless as they are rusted. I was just going to use it for the auto swap and 4:1 transfer case, then sell the axles to get most of the money back out of it.

In that case, someone more intimately familiar with hacking the wiring to interface the 00 with the 04 trans will have to say whether it is doable or worth it. I tend to copy factory and use it how they did it. That means if I was doing it, I'd have to convert the 00 to be an 04 with all the harnesses and emissions group which also means moving the fuel tank over. The only thing that may save you is the separate TCM.

 

[mjonesjr84]

In that case, someone more intimately familiar with hacking the wiring to interface the 00 with the 04 trans will have to say whether it is doable or worth it. I tend to copy factory and use it how they did it. That means if I was doing it, I'd have to convert the 00 to be an 04 with all the harnesses and emissions group which also means moving the fuel tank over. The only thing that may save you is the separate TCM.

I wouldn't want to hack the wiring up. If I were to go this route, I'd convert to the '04 as well. I'm going to keep on the hunt for a '00 to just swap the transmission over.

 

[mrblaine]

I'm going to keep on the hunt for a '00 to just swap the transmission over.

97-02 will all be close enough to the same to work.