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32RH (3 speed) versus 42RLE (4 speed)

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#21 ·
RDBills said:
My opinion of the 42RLE in my jeep markedly improved after I installed 5.38 gears to better match my 35" tires. I suspect that many complaints about the 4 speed auto involve jeeps geared too tall (numerically low) for the tire size being used.
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Yes, that was true, and justifiable since you couldn't get anything deeper than a 4.88 for a dana 30 until pretty recently. Now multiple companies offer 5.13 and 5.38's, so that issue has been resolved.

If I was in the market for another TJ, I would still prefer one with a 32rh, but the newest one would still be 15 years old and are getting pretty hard to find in decent shape. So, I wouldn't take a 42rle off the table, but I'd want one that I knew for sure had been treated relatively well and I'd throw a good cooler on it asap.
 
#22 ·
RDBills said:
My opinion of the 42RLE in my jeep markedly improved after I installed 5.38 gears to better match my 35" tires. I suspect that many complaints about the 4 speed auto involve jeeps geared too tall (numerically low) for the tire size being used.
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Mine got better with 4.88s and 32" tires but it's still poor programming that's to blame. On paper what the transmission is trying to do is save on gas when in reality it makes gas mileage worse.
 
#23 ·
RDBills said:
My opinion of the 42RLE in my jeep markedly improved after I installed 5.38 gears to better match my 35" tires. I suspect that many complaints about the 4 speed auto involve jeeps geared too tall (numerically low) for the tire size being used.
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I agree. My TJ and its 42RLE with 35" tires is overall much better behaved in all regards since regearing from being undergeared with 4.88 to 5.38. The Jeep is much better behaved on the highway, and that both the engine and transmission are "happier" with the new lower 5.38 ratio is easily felt.
 
#24 ·
TJTurbo said:
I see your point, but at the same time there is still a fairly large market for TJ owners.
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Hanging around a site like this might make it seem that way, but if you break it down the potential sales are limited relative to other vehicles. Going big picture how many after market companies of any type are doing anything new these days for TJs? It's limited. But when it comes to this transmission, there were probably less than 200k total TJs made with it and a good chunk of those are off the road already (with less on the road every day). How many left on the road are on stock tires where it is less of an issue? And how many owners pay that much attention that they would think about this, find the product and 'be willing to pay what it costs? JF members and owners like them are a small fraction of owners. And even within however many potential buyers are left after that it is not one set of code to crack. 03-06 I think used at least 2, maybe 3, different sets. Vendors have limited resources and have to consider all opportunities. They will pick the markets with biggest expected profitability relative to resource commitment and this is not it.
 
#25 ·
biffgnar said:
Hanging around a site like this might make it seem that way, but if you break it down the potential sales are limited relative to other vehicles. Going big picture how many after market companies of any type are doing anything new these days for TJs? It's limited. But when it comes to this transmission, there were probably less than 200k total TJs made with it and a good chunk of those are off the road already (with less on the road every day). How many left on the road are on stock tires where it is less of an issue? And how many owners pay that much attention that they would think about this, find the product and 'be willing to pay what it costs? JF members and owners like them are a small fraction of owners. And even within however many potential buyers are left after that it is not one set of code to crack. 03-06 I think used at least 2, maybe 3, different sets. Vendors have limited resources and have to consider all opportunities. They will pick the markets with biggest expected profitability relative to resource commitment and this is not it.
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Makes sense, after looking at some production figures online for '05-'06 TJs I thought the number would be higher than it was.
 
#26 ·
TJTurbo said:
Makes sense, after looking at some production figures online for '05-'06 TJs I thought the number would be higher than it was.
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If a vendor can create a product that sells to the entire TJ model run and doesn't differentiate between transmissions (let's say a bumper) it has a much bigger potential market (10-20x) rather than something that only can be sold to maybe 1 or 2 years of autos only (given the way Jeep handled their programming). It is disappointing as probably just about every 42RLE owner on JF would be interested, but just not enough of us.
 
#27 ·
biffgnar said:
I believe it was rebuilt before each race
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I didn't know they rebuilt it more than once but then again I don't know too much about it, the last time I saw that LJ it had an LS in it with no RLE in sight.

I have read several stories of 32RH transmissions failing on the trail but don't remember any stories of 42RLE failures on the trail, they all seem to limp home and then croak. Anybody seen a 32RH catch on fire, die on the trail, 42RLE?
 
#30 ·
biffgnar said:
Anecdotal results here on JF over the years clearly leans toward more issues with the 42RLE. Non-scientific sure and subject to some biases, but if you look at a big enough window it has to tell you something.

You are correct that the Savvy/Currie LJ ran the 42RLE. And I while I believe it was not internally upgraded in any real way, I believe it was rebuilt before each race and ran with supplemental cooling, as is always discussed when we get in to the reliability of this transmission. That rebuild, which is typical for race cars, makes it a bit of apples to oranges when it comes to a discussion of reliability versus our use, although the few hundred miles it has to last (pre-running and race day) are not easy miles.

Keeping the 42RLE cool is the biggest key for us. Granted I live somewhere relatively flat so my miles have been easier than some, but I'm at 164k miles and counting with no real issues with mine.
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The 42RLE in the first 88 car was built by Westminster Transmission. He wasn't able to upgrade any of the parts because they weren't available at that time. It was the only complex component on that car that was never gone through for the entire time it was raced and that was with a 300 hp stroker in front of it.
 
#31 ·
jjvw said:
Am I correct that there is no good way to swap the 32RH into a late-TJ? I recall something about the torque converter lock up not working. If my NV3550 ever gave out, I would consider an auto if there was a decent swap available.
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It shouldn't be that hard if you don't mind a lock-up switch on the dash. Since your PCM isn't looking for any auto trans input or outputs, it should be happy with the 32RH in there. I'm guessing since you have the 3550 that your CPS is on the passenger side?

edit- alright, thinking a bit more, why don't we start with the year and go from there?
 
#32 ·
mrblaine said:
It shouldn't be that hard if you don't mind a lock-up switch on the dash. Since your PCM isn't looking for any auto trans input or outputs, it should be happy with the 32RH in there. I'm guessing since you have the 3550 that your CPS is on the passenger side?

edit- alright, thinking a bit more, why don't we start with the year and go from there?
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2003 Rubicon. I'm curious to see how feasible this might be.
 
#33 ·
jjvw said:
2003 Rubicon. I'm curious to see how feasible this might be.
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Very feasible. The 03 has a 3 plug PCM. I believe that you can set up the lock up circuit without any ill effects. One of them would be forgetting to unlock it when you come to a stop and having it kill the motor but I think there is no way to lock it in first gear so it automatically unlocks or isn't locked in first depending on how it's done.

It should also be simple to set it up with a trigger to a latching relay that unlatches with a trigger input from the brake pedal sense circuit similar to how the cruise kicks off when you touch the brakes.

The rest is basic mechanical and not difficult.
 
#34 ·
mrblaine said:
Very feasible. The 03 has a 3 plug PCM. I believe that you can set up the lock up circuit without any ill effects. One of them would be forgetting to unlock it when you come to a stop and having it kill the motor but I think there is no way to lock it in first gear so it automatically unlocks or isn't locked in first depending on how it's done.

It should also be simple to set it up with a trigger to a latching relay that unlatches with a trigger input from the brake pedal sense circuit similar to how the cruise kicks off when you touch the brakes.

The rest is basic mechanical and not difficult.
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Very interesting. The brake pedal trigger makes sense. This could become a future project in a few years.
 
#35 ·
We did a 5.7 swap on my son’s yj last summer. The new wiring harness included a circuit that ties in with the switch on the brake pedal to unlock the TC. IIRC we soldered the new wire into the wire on the brake switch that sends voltage to the brake lights.
 
#36 ·
TJR238 said:
We did an LS swap on my son's yj last summer. The new wiring harness included a circuit that ties in with the switch on the brake pedal to unlock the TC. IIRC we soldered the new wire into the wire on the brake switch that sends voltage to the brake lights.
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How is the lock up accomplished? Is there a manually activated dash switch?
 
#40 ·
jjvw said:
Well that's no help! ;)
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:laugh:
Just lettin' you know a brake switch is 'doable.'

I did a lot of reading up before getting my rubi. I understand the benefit of increased torque with the auto but decided not to go with the auto because the 32RH likes to drink in water and I do a lot of water crossing. The 42RLE has the overdrive and PCM problems. My son said the auto is way better on the trails than his old manual. Gotta pick your poison.
 
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