[CB3]

OK, what's the deal with this transmission?

I've heard conflicting info on it. Is it really 4 speeds + OD or what's the deal?

I've heard it has 4 gears + OD, but what does that mean? Is the OD a 5th gear? Is the OD a lockup torque converter? What?

Is the 4th gear the OD? What about the lockup torque converter? Does it only lock in 4th gear? Does it always lock in 4th gear?

Does the torque converter lockup give the equivalent of a 5th gear?

Will the torque converter lock in every gear, some gears, or only 4th gear?

When I use the OD Off button in my 06 Rubi LJ, what does that actually do? Does it just prevent it from shifting to 4th gear, or does it just prevent the torque converter from locking up, or does it do both those things?

I love this transmission and I think it's the best auto tranny I've ever had. I had one in my 96 XJ and I loved it. Have one in my 06 LJ Rubi and love it. However, even though I love it, I've never understood what it does or how it does it.

Most of all I want to understand how many gears it really has, which of those gears the torque converter can lock up in, and what does my OD off button really do?

Also, what is the ideal rpm for cruising on a level freeway at 68 mph with a 2006 4L 242 engine and the 42RLE - 4 Speed Auto with Overdrive transmission. I have 33" X 11.5" tires and am thinking of changing my rearend gearing to 4.88. However, what is the ideal rpm for cruising on a level freeway at 68 mph? I mean ideal for gas mileage.

[Unlimited04]

the 42RLE is a 4 speed transmission. 1st, 2nd, 3rd (OD OFF) and 4th (OD).

You push the OD OFF button, it doesn't let the tranny go to 4th gear. this is useful for towing, driving in the hills and 4Lo. This was NOT the transmission you had in your 96 XJ, that was an AW4.

Ideal gas mileage driving will be about 60mph (with 30s and 3.73s, or 31s and 4.10s). For you, with 4.11s and 33's, there is no idea speed, since you're speedo calibration hasn't been updated and you haven't regeared.

the 42RLE sucks a lot of power out of the 4.0L, it takes a significant amount of torque to power it, doesn't mean its not a good tranny, but it sure is a pain in the mountains. I find it has weird shift points, doesn't shift when i want it to, or shifts into OD way to quick @ 45mph. Personally, i think the 42RLE was meant for an engine with 40 more hp, because to me, it sure seems like the 4.0L is missing a lot of grunt. there is a shift kit for it that supposedly makes it shift smoother and at the right time, i'll have to try that eventually.

[devildg]

Originally Posted by Unlimited04

the 42RLE is a 4 speed transmission. 1st, 2nd, 3rd (OD OFF) and 4th (OD).

You push the OD OFF button, it doesn't let the tranny go to 4th gear. this is useful for towing, driving in the hills and 4Lo. This was NOT the transmission you had in your 96 XJ, that was an AW4.

Ideal gas mileage driving will be about 60mph (with 30s and 3.73s, or 31s and 4.10s). For you, with 4.11s and 33's, there is no idea speed, since you're speedo calibration hasn't been updated and you haven't regeared.

the 42RLE sucks a lot of power out of the 4.0L, it takes a significant amount of torque to power it, doesn't mean its not a good tranny, but it sure is a pain in the mountains. I find it has weird shift points, doesn't shift when i want it to, or shifts into OD way to quick @ 45mph. Personally, i think the 42RLE was meant for an engine with 40 more hp, because to me, it sure seems like the 4.0L is missing a lot of grunt. there is a shift kit for it that supposedly makes it shift smoother and at the right time, i'll have to try that eventually.

Hey unlimited, do you know who makes that shift kit because ive been looking forever and cant find one

[robncar]

Just as Unlimited04 said, the OD off button keeps the trans from shifting into overdrive and stops at third gear.

The 42RLE transmission ratios are:

First 2.84 : 1
Second 1.57 : 1
Third 1.00 : 1
Overdrive 0.69 : 1
Reverse 2.21 : 1

[BlueFlame]

As said above, it's a 4 speed auto, with 4th being overdrive.
When you put it in gear and drive away, you can easily count the shifts...
plus you can usually feel a "shudder" when the tConv locks up- feels different than a shift, but kinda similar, should feel it in 3rd around 35-40 mph.

I believe the computer will lock up the torque converter only in 3rd and 4th.

Unlimited04 is correct about the trans not seeming like it matches the engine - it doesn't. DC never did the R&D to match the transmission gear ratios to the 4.0 and it's somewhat out of sync with the engine output. Plus the programming is trying to force economy so its decision-making process is wrong for performance as well (upshifts too soon and isn't very responsive to throttle position.) That's why its a bigger "power sucker" than most autos and performance isn't optimal.

[devildg]

Yeah, I hate the way it shifts. Really sloppy, and slow. I would really like to have a 700R4 but that is probably not in the budget. Anyone else know of a shift kit?

[chefdab]

I believe the shift kit is made by Transgo. They don't have the 42 RLE listed on their site but I know several Liberty owners who have added a shift kit to their trannys. (The KJ uses the 42rle also.)

Maybe check over on LOSThttp://www.lostkjs.com and see if you can find out which one they are using.

[CB3]

Well then, I guess it was the AW4 in my XJ that I loved. Did it have 4 gears too? Did its torque converter lock up in both 3rd and 4th? Did it have a 4th gear?

=====

FYI - my XJ weighed 3400 lbs stock. My LJ Rubi weighs 4300 lbs stock. That is according to the local truck scale at the local dump.

So I think one reason the LJ Rubi is a dog on the road compared to my XJ is that the same engine in both, but the LJ Rubi weighs 900 lbs more.

Don't you think that might be part of the LJ Rubi's crummy street performance?

I think this engine and tranny 42RLE are good, but the vehicle is just a fat pig in weight. Sure, if the tranny let it wind up more before upshifting, that would help compensate. Like giving a fat boy more muscle, but he'd still be heavy, and he's still going to be slow in a race.

[CB3]

So do I understand you fellas correctly that the torque converter will automatically lockup in both 3rd and 4th gears? If so, that makes me happy.

I think some regearing diffs to 4.88 to go with my 33" tires will help a lot.

Now that shift kit you guys are talking about.... What does it do? Let engine wind up more before shifting?

[BlueFlame]

Originally Posted by CB3

Well then, I guess it was the AW4 in my XJ that I loved. Did it have 4 gears too? Did its torque converter lock up in both 3rd and 4th? Did it have a 4th gear?

Yes, it was a 4 speed (fourth being overdrive) and the tC did lock up, as do all modern 4 (and 5 and 6) speed transmissions. Even the old 3 speed auto in it's last incarnation had lockup.

Torque converter lockup essentially does 2 things - lets more engine power go thru for less "power loss" and more effeciency (improves both power and gas mileage) and due to less slippage, reduces generation of heat - the single biggest killer of automatic transmissions.

[BlueFlame]

Originally Posted by CB3

So do I understand you fellas correctly that the torque converter will automatically lockup in both 3rd and 4th gears? If so, that makes me happy.

I think some regearing diffs to 4.88 to go with my 33" tires will help a lot.

Now that shift kit you guys are talking about.... What does it do? Let engine wind up more before shifting?

Yep.

Yep.

Different shift kits do different things. For popular transmissions there are often more than one kit to choose from. One for improved response, better shift points, quicker shifts (not as mushy,) etc. One for street performance (high performance big 'muscle car' type of performance. One for RV/Towing for use in trucks. etc..

For example, this is what the Transgo Shift Improver kit SKE4OD (the transmission in my F150) does:
"Transgo SKE4OD shift kit for the 1989-UP E4OD and 4R100 transmissions. This kit corrects the common problems with these transmissions; Reduces, Prevents, & Corrects, Soft shifts, Converter burnup, reverse delay, converter slide or shudder, no reverse when hot, 2nd and 3rd burnup, pump buzz. Along with fixing these common problems, you'll also see an increase in the life of your transmission due to the reduced slippage."

That transmission (E4OD) is notoriously mushy, shifts are painfully slow and soft (they probably do this for smooth ride for old folks...) especially bad when loaded or towing, and it upshifts too early, and it kicks out of lockup with the slightest touch of throttle then quickly relocks - so you waste a burst of fuel for no gain in speed or power. The shift kit firms up the shifts, changes the points at which it shifts, controls lockup better, and shortens the overlap during shifts. (What overlap is: When an auto shifts from one gear to the next, the 2 gears are both briefly engaged at the same time,both slightly slipping as one lets go and other comes on. The longer this overlap exists, generally the smoother the shift. BUT, it wastes horsepower, generates lots of heat, and causes extra wear.) The kit comes with enough parts to allow the installer to custom tailor his installation to the needs/desires of the driver, some like BAngSudden shifts, some just want firmer but not abrupt shifts etc.

They also have a kit for diesel/towing applications. It makes different changes to improve the trans for those needs.

If you are a confident, competent mechanic you could generally install a shift kit yourself in most transmissions. But if you doubt even for a minute that you could do it, you probably shouldn't try it, take it to a shop. If you have it installed while having your trans serviced, expect to pay an extra 1 to 2 hours of shop time.

I cannot find any reference to a shift kit for the 42RLE.

[CB3]

Regarding XJs and AW4 transmission:

Originally Posted by BlueFlame

Yes, it was a 4 speed (fourth being overdrive) and the tC did lock up, as do all modern 4 (and 5 and 6) speed transmissions. Even the old 3 speed auto in it's last incarnation had lockup.

Torque converter lockup essentially does 2 things - lets more engine power go thru for less "power loss" and more effeciency (improves both power and gas mileage) and due to less slippage, reduces generation of heat - the single biggest killer of automatic transmissions.

Did the AW4 transmission torque converter lockup in both 3rd and 4th gears, or only in 4th?

I'm asking because I'm seriously considering buying another XJ of the 98 model year.

[CB3]

Personally I'm happy with my 42RLE very much, except for 2 things: It shifts into overdrive way to soon, thus forcing me to use the OD off button so much that it's like the 3rd and 4th gears are a manual transmission thanks to the hassles for me. The other thing I don't like is the torque converter lockup has no balls whatsoever and disengages way to easily.

So I'd like to delay the shift to OD until rpms are higher, say maybe around 2400 rpm, and I'd like that darned torque converter lockup to stay locked up with more force so it can pull a hill and stay locked when the engine isn't lugging.

The shift points of the other gears are fine with me as is, but might be even a little better if it wound up the rpms another 200 rpms higher before shifting. But it's not bad as is, except the shift point from 3rd to 4th being way to soon.

[robncar]

Originally Posted by CB3

So do I understand you fellas correctly that the torque converter will automatically lockup in both 3rd and 4th gears? If so, that makes me happy.
I think some regearing diffs to 4.88 to go with my 33" tires will help a lot.
Now that shift kit you guys are talking about.... What does it do? Let engine wind up more before shifting?

Originally Posted by CB3

Personally I'm happy with my 42RLE very much, except for 2 things: It shifts into overdrive way to soon, thus forcing me to use the OD off button so much that it's like the 3rd and 4th gears are a manual transmission thanks to the hassles for me. The other thing I don't like is the torque converter lockup has no balls whatsoever and disengages way to easily.

So I'd like to delay the shift to OD until rpms are higher, say maybe around 2400 rpm, and I'd like that darned torque converter lockup to stay locked up with more force so it can pull a hill and stay locked when the engine isn't lugging.

The shift points of the other gears are fine with me as is, but might be even a little better if it wound up the rpms another 200 rpms higher before shifting. But it's not bad as is, except the shift point from 3rd to 4th being way to soon.

When you install the 4.88's, with your 33's, you'll say it was the best thing you ever did. Your OD off button will be, for the most part, out of your life on the street.

[BlueFlame]

Originally Posted by CB3

Regarding XJs and AW4 transmission:



Did the AW4 transmission torque converter lockup in both 3rd and 4th gears, or only in 4th?

I'm asking because I'm seriously considering buying another XJ of the 98 model year.

I don't know for certain. I'd bet it does. Most modern autos even lockup in 2nd. You might ask on the XJ forum.
Note: A 5 speed locks up in all gears....