How do you use your 42RLE overdrive?

Yuan said:
Drove the LJ today with O/D on and off at different speeds--just for the heck of it. LOVE the throttle response and acceleration with O/D off around 40-65 mph range. Wondering why Chrysler did what it did with the o/d feature. Well, at least now I know what button to push when the RPM wouldn't go beyond 2k.
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I had a couple of basically 70's era cars (Spitfire and Volvo) that both had OD, but it was a toggle switch usually in the off position. My '95 F250, the opposite - the OD needs to be switched-off as is the case with the TJ. So...pretty common feature with differing applications and I think in this case Chrysler didn't have the TJ in mind - pretty sure this is used in the KJ series and perhaps the Durango, which are way more pedestrian . But, the purpose seemed mostly to be to reduce engine RPM at highway speed at the expense of torque, I presume in order to improve EPA mileage rating. Also, some people get uncomfortable with higher RPMs.
 
LJ Jim said:
Can you link to this post please? I searched but no luck.
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I'm interested in this too. Looks like their tuner is $300.

My main complaint is driving up a mountain with OD off. When I start losing speed, I have to push the gas further, then the RPM's quickly climb to 4000+. I get a little speed (catch up to the car in front of me) and take my foot off the gas so the RPM's stop climbing.

If the tuner will help with this, I might be interested.
 
suicideking said:
I'm interested in this too. Looks like their tuner is $300.

My main complaint is driving up a mountain with OD off. When I start losing speed, I have to push the gas further, then the RPM's quickly climb to 4000+. I get a little speed (catch up to the car in front of me) and take my foot off the gas so the RPM's stop climbing.

If the tuner will help with this, I might be interested.
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The problem with mine as stock, was that anything past 50% throttle made very little if any difference in power. I think past 75% throttle it may have even lost power. Once I saw the timing tables I understood why it struggled past half throttle. Making minor changes to a small portion of the table made a very noticeable difference and knew there was more to come. My Jeep is a daily driver and many hills would slow me down from 70 mph to less than 65 with the stock tune. With my current tune on those same hills I can gain speed. It is by no means push you back in the seat acceleration, but I am not in the way. With cruise control set at 80 mph a couple of hills will slow me down to 75, but mpg is horrible at 80 mph.
 
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We are all so spoiled!!!! The TJ with an auto and stock fuel injected 4.0 is a beast when compared to my 84 CJ8. Jeeps are generally designed with a eye toward off road use so their on road manners and power are not really like a passenger car...they get by but yeah you may slow down going up a hill.

Not poking fun but everyone has forgotten (or has never experienced) how Jeeps/trucks used to be... My neighbor who is like 80 borrowed my CJ and complained that he couldn't use 5th gear going up a hill (it only has 100 hp from it's carbureted 258) and I asked him what did he do when driving a truck in the 60's? He was like, oh yeah, downshift, slowdown, and enjoy the scenery cause you ain't gonna go any faster.

I figure it's part of the Jeep appeal...its not built like other cars and won't perform like them. It's noisy, slow, rough riding, bad on gas, and just the way we like it :)

That being said, yeah, I switch off my OD on hills, and generally just slow down to keep it from shifting into 2nd and the having the RPMs hit 4000.
 
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84 Scrambler said:
We are all so spoiled!!!! The TJ with an auto and stock fuel injected 4.0 is a beast when compared to my 84 CJ8. Jeeps are generally designed with a eye toward off road use so their on road manners and power are not really like a passenger car...they get by but yeah you may slow down going up a hill.

Not poking fun but everyone has forgotten (or has never experienced) how Jeeps/trucks used to be... My neighbor who is like 80 borrowed my CJ and complained that he couldn't use 5th gear going up a hill (it only has 100 hp from it's carbureted 258) and I asked him what did he do when driving a truck in the 60's? He was like, oh yeah, downshift, slowdown, and enjoy the scenery cause you ain't gonna go any faster.

I figure it's part of the Jeep appeal...its not built like other cars and won't perform like them. It's noisy, slow, rough riding, and just the way we like it :)

That being said, yeah, I switch off my OD on hills, and generally just slow down to keep it from shifting into 2nd and the having the RPMs hit 4000.
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Now I feel guilty for what I’ve done to my little poor LJ...

:)
 
I sort of wish the overdrive button was backwards in my TJ. Off when you get in and start it, and I will turn it on when I see fit. And I have 5.13's with 35's, that are really 34" tall. Mine spins 2500 rpm at 70 in OD.

Use the button all you want OP. Turn it off all the time if you want like others have said.
 
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Brianj5600 said:
The problem with mine as stock, was that anything past 50% throttle made very little if any difference in power. I think past 75% throttle it may have even lost power. Once I saw the timing tables I understood why it struggled past half throttle. Making minor changes to a small portion of the table made a very noticeable difference and knew there was more to come. My Jeep is a daily driver and many hills would slow me down from 70 mph to less than 65 with the stock tune. With my current tune on those same hills I can gain speed. It is by no means push you back in the seat acceleration, but I am not in the way. With cruise control set at 80 mph a couple of hills will slow me down to 75, but mpg is horrible at 80 mph.
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I've noticed the same on my 99. What's also weird is if I run my Torque app with my obd2 scanner, "engine load" doesn't really even increase much past about half throttle. Since engine load is based on airflow, I just blamed it on the throttle body being bigger than it needed to be and at about half throttle was flowing all the intake/cam/head would allow.
 
Cross-Threaded-06TJ said:
I sort of wish the overdrive button was backwards in my TJ. Off when you get in and start it, and I will turn it on when I see fit. And I have 5.13's with 35's, that are really 34" tall. Mine spins 2500 rpm at 70 in OD.

Use the button all you want OP. Turn it off all the time if you want like others have said.
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My guess is the EPA wouldn't have let them count on OD in their fuel economy test if it wasn't on by default.

Almost 20 years ago I was driving an early 80's Volvo that had a 4 speed manual plus an overdrive that was activated by a button, on top of the shift knob if I remember correctly. Since the car was already old and didn't have an owners manual, and the internet was just taking off, I never did figure out whether I was supposed to step on the clutch pedal when I pushed the button or whether there was an internal clutch mechanism in the OD that took care of it. So I just used the clutch to to be safe.
 
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Have been reading up on 42RLE vs 32RH on the www. This caught my eye--"just turn off O/D and pretend you have a 32RH". Is this a legit way to look at/go about it? Gear ratios on both appear to be nearly identical at 1, 2 and 3rd after all. I really like how it drives at near highway speeds(45-60) with o/d off--it sounds, feels and accelerates much more like the 4th/5th gears on the 6-spd manual(NSG370?) that I happen to have a bit more experience with. In the previous 2-3 weeks that I have been driving the LJ with o/d on the entire time--sometimes it was a hard to believe it's the same 4-liter under the hood.
 
Cross-Threaded-06TJ said:
I sort of wish the overdrive button was backwards in my TJ. Off when you get in and start it, and I will turn it on when I see fit. And I have 5.13's with 35's, that are really 34" tall. Mine spins 2500 rpm at 70 in OD.

Use the button all you want OP. Turn it off all the time if you want like others have said.
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thx. that's what I plan to do...based on my little experiment last couple days and input from this forum.
 
Some have wired theirs to automatically send an OD off signal to the PCM when the shifter hits reverse, like when being shifted from park to drive.
 
Irun said:
I know some don't like it, but the 42RLE isn't as bad as the internet makes it out to be. I've had several and they have all proven themselves to be reliable, with the one in my previous '03 going 190K miles before it gave up. Also, some of the 42RLE related problems were not actually the transmission, but rather Chrysler bumbling the '05 - '06 PCM changes. They knew they had a problem with the PCM and just abandoned customers who bought them. Thank goodness for WranglerFix, because they took on solving a problem Chrysler wouldn't!

That said, the overdrive and shift points aren't ideal, but gearing can help with the drivability, to a point. Making the transmission last isn't difficult, if you follow these guidelines:

- Overdrive - leave it off in town and on during highway driving
- Install a good stacked plate transmission cooler and temperature gauge
- Change the fluid regularly, using only ATF4 and
- Re-gear the differentials, based on tire size
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I love you (‘05 owner)
 
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