Changing the 42RLE shift points?

Not to derail things, but:

Unfortunately you can't install a transmission such as the GM 4L60E for instance. It's computer controlled just like the 42RLE, and the Jeep PCM has no way of talking to it and telling it when to shift, etc.

Unless I'm recalling some research incorrectly, you can install an early 4L60E with the correct adapter, but you have to install a stand-alone transmission controller in order to make it function...and that's expensive. Like, $1000 of expensive...but I'm pretty sure Novak carries the required widgets if you want to pony up for them. Likewise, I think you can install the earlier 700R4, which requires no controller, but - again - it still requires adapters. Then, you get to have fun with the T-case, but there are some ways to handle that, too.

Thus endeth the derail.
 
Not to derail things, but:



Unless I'm recalling some research incorrectly, you can install an early 4L60E with the correct adapter, but you have to install a stand-alone transmission controller in order to make it function...and that's expensive. Like, $1000 of expensive...but I'm pretty sure Novak carries the required widgets if you want to pony up for them. Likewise, I think you can install the earlier 700R4, which requires no controller, but - again - it still requires adapters. Then, you get to have fun with the T-case, but there are some ways to handle that, too.

Thus endeth the derail.
The trans gets to be the cheap part of that install. Last I saw, the adapters for the 700R4 were over a grand and with another grand for a controller, that gets expensive fast for parts. That and you get to own a few converter swaps along the way if the local experiences are any indicator. All the ones I know about have finally pulled the 700 out because the converters are very difficult to find the right stall rating for in the Jeep.
 
The trans gets to be the cheap part of that install. Last I saw, the adapters for the 700R4 were over a grand and with another grand for a controller, that gets expensive fast for parts. That and you get to own a few converter swaps along the way if the local experiences are any indicator. All the ones I know about have finally pulled the 700 out because the converters are very difficult to find the right stall rating for in the Jeep.

I didn't think that the 700 or the early 4L60 used any sort of controller at all, but I could be wrong about that; I know for sure that the 4L60E does, and it's right about a thousand bucks, as stated. I think the 700R4/4.0 adapter is $450 from Novak, but I've zero experience with it; I just know that it exists. Likewise, I'm not sure about the converter, but I've also heard that they can be difficult to get set up correctly. No argument that it's not cheap and may not be very smart; I just wanted to point out that it's possible. I should probably look into it; I have a 42RLE that's been less-than-impressive.
 
I didn't think that the 700 or the early 4L60 used any sort of controller at all, but I could be wrong about that; I know for sure that the 4L60E does, and it's right about a thousand bucks, as stated. I think the 700R4/4.0 adapter is $450 from Novak, but I've zero experience with it; I just know that it exists. Likewise, I'm not sure about the converter, but I've also heard that they can be difficult to get set up correctly. No argument that it's not cheap and may not be very smart; I just wanted to point out that it's possible. I should probably look into it; I have a 42RLE that's been less-than-impressive.
I'm waiting on the "we have it done and it is working perfectly" answer for the wheel speed sensor relocator so I can play with a NAG1 swap. As soon as I get that answer, I'm getting the trans and will start building the adapters for it.

If I am going to spend that much on a stand alone controller, I want it to be shifting a spiffy trans.
 
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I just did a little looking-up: the earlier 700R4 and the non-electronic 4L60 do not require a controller, but you can be into just as much expense with the TV cable, governors, etc, etc. The 4L60E requires a controller, so the expense basically is a wash between the two. The E will also cost a bit more money up front.

I've no knowledge of the NAG1, aside from the fact that it's a transmission.
 
Yep, the OD is off until I get up over 65-70 mph. Never on around town.

Blaine what RPMs are you comfortable running the 4.0/42RLE for extended-ish (10+miles)? I think part of my frustration and hatred for the 42RLE is I always feel like im doing something wrong when my tach hits 3K. For me its really 60mph that is my worst spot. 3rd gear is over 3K and OD is 2.1K.
 
Blaine what RPMs are you comfortable running the 4.0/42RLE for extended-ish (10+miles)? I think part of my frustration and hatred for the 42RLE is I always feel like im doing something wrong when my tach hits 3K. For me its really 60mph that is my worst spot. 3rd gear is over 3K and OD is 2.1K.
You can run all day at 3,000 RPM without issue.
 
With my 4:10s and 33" tires, I actually have a sweet spot where I can use OD around town, and I actually see a bit higher mpg (according to the Torque app) It's around 50 - 60mph. Beyond that, like on the highway, punching a hole in the air gets to be the problem and I need to turn the OD off. On our cross country trips, I have run for hours on end over 3000 RPM. Some of the steep climbs out of Denver have me in 2nd gear pulling some serious RPM. Oil changes every 5k or after every big trip when the Jeep works hard, and so far all the oily bits are staying inside the engine where they belong at 155k miles. <knocking on my desk>
 
ah that should make me hate the 42RLE less. When i drive to a wheeling spot i drive a highway that is 55mph and hilly. OD is basically non-functional.
 
With my 4:10s and 33" tires, I actually have a sweet spot where I can use OD around town, and I actually see a bit higher mpg (according to the Torque app) It's around 50 - 60mph. Beyond that, like on the highway, punching a hole in the air gets to be the problem and I need to turn the OD off. On our cross country trips, I have run for hours on end over 3000 RPM. Some of the steep climbs out of Denver have me in 2nd gear pulling some serious RPM. Oil changes every 5k or after every big trip when the Jeep works hard, and so far all the oily bits are staying inside the engine where they belong at 155k miles. <knocking on my desk>

How the heck do you keep the oily bits inside? Did you change the RMS? Mine weeps like Mary. Haha.
 
Currently running synthetic. It leaked with conventional also. It's not as bad as I make it out, but lets just say my oil pan wont rust.
 
I developed the habit of turning the OD off as a normal part of start up. I rarely drive the TJ on the highway so the fastest I go is around 45 to 50. But I did get the impression that cancelling the OD does something to the shift points. Could be my imagination, but I could swear it feels different at lower speeds. Maybe one of you could convince me that there is no difference and I imagine it.
 
I developed the habit of turning the OD off as a normal part of start up. I rarely drive the TJ on the highway so the fastest I go is around 45 to 50. But I did get the impression that cancelling the OD does something to the shift points. Could be my imagination, but I could swear it feels different at lower speeds. Maybe one of you could convince me that there is no difference and I imagine it.
I notice the same thing, it does shift differently depending on if the OD is on or turned off.
 
It for sure locks TC in 3rd. So if a hill is steep and is about 30mph i will keep in OD so it stays unlocked otherwise its similar problem to going 55mph in OD... now powah.
 
I developed the habit of turning the OD off as a normal part of start up. I rarely drive the TJ on the highway so the fastest I go is around 45 to 50. But I did get the impression that cancelling the OD does something to the shift points. Could be my imagination, but I could swear it feels different at lower speeds. Maybe one of you could convince me that there is no difference and I imagine it.

42RLE Manual

42RLE Gear Ratios:

1st Gear - 2.84:1
2nd Gear - 1.57:1
3rd Gear - 1.00:1
4th Gear - 0.69:1
Reverse - 2.21:1

Overdrive ON:

1st, 2nd, 3rd, 4th, TCC Lockup in 4th gear

Overdrive OFF:

1st, 2nd, 3rd, TCC Lockup in 3rd gear

Note: The TCC will lockup in 3rd or 4th gear, not both 3rd and 4th gear.

Next time you go for a drive and start out with overdrive OFF, pay attention to the RPMs as well your your ability to accelerate when the transmission shifts into 3rd gear. With overdrive OFF, the TCM/PCM will immediately lockup the TCC after the 2-3 shift occurs, regardless of load or throttle position. The TCC will then remain locked or unlock depending on load and throttle position. The dead spot you feel in the throttle is the TCC locking up.

If you start off with overdrive ON, the TCC will not lockup until after the 3-4 shift occurs and then only if load and throttle position allow.

I use the O/D switch all the time. If I am able to accelerate up to 65 MPH+, I just leave overdrive on. The transmission will shift through all of the gears at the appropriate RPMs and when I am up to speed the TCC will lockup as soon as reach my cruising speed and ease off the throttIe.

If I need to drive between 40 MPH-55 MPH, I start out with overdrive ON and then turn overdrive OFF after the 2-3 shift occurs but before the 3-4 shift. This allows the TCC to lock up in 3rd gear at RPMs high enough that it remains locked.
 
Reviving this old 42RLE shift-point thread rather than starting a new one - it's a good one! Happy to repost to a new thread if this is bad form ...

Anyway ...

This is probably auto-trans 101 stuff, but what determines when the tranny kicks it up or down? I know ... it's the "shift points" stupid ... but what does that mean exactly? Are those simply pre-set RPM combinations programmed into the ECM (which I gather cannot be changed in this case) and the ECM electronically controls the transmission such that the lever is signaling the ECM and the ECM is signaling the transmission, for example? To determine what the shift points are, is it as simple as noting what the RPMs are when the 42RLE shifts and it will always up or down shift at that RPM? I'm familiar with the concept as a practical matter - I've got two vehicles that have multiple shift point profiles and fool around with those, but I don't actually know how it works.

Like many other 42RLE folks, I made a choice that I can live with when I got the rig. I'm about to drop some coin on re-gearing and I've been fooling around with the Grimjeeper calculator and thinking about where I want to land RPM-wise for the kind of driving I usually do and really not sure whether the re-gear to 4.88 or 5.13.

(Also, FWIW, I similarly disable the OD once underway almost always and prefer to run the engine in the high 2's, low-to-mid 3's. Hardly ever on the interstate with the TJ, mostly the primary and secondary roads at ~ 50 mph and off-road ~ 25 mph in a very hilly area. With the original 3.73 gears and 32s, I'm setting the lever to position 2 just about all the time and running in the 2800-3500 rpm range for the bulk of my driving with 3 essentially functioning as my manual OD - I kick the lever to 3 when I get to a level ground cruising speed.)
 
This is probably auto-trans 101 stuff, but what determines when the tranny kicks it up or down?
The TCM uses lots of information to determine when to shift: load or intake manifold pressure; throttle position; transmission temperature; O/D on or off; input shaft speed, gear selection, and adaptive behavior like how aggressive you are driving.
 
The TCM uses lots of information to determine when to shift: load or intake manifold pressure; throttle position; transmission temperature; O/D on or off; input shaft speed, gear selection, and adaptive behavior like how aggressive you are driving.
Aha. So, no way really to predict the shift points for planning purposes then. I can calc what the speed & RPM are for each gear, but I can't know when the tranny will actually up or down shift except via road testing and the results will vary by driving condx.

I can see why there's a lot of wishful thinking about re-programming shift points on the 42RLE then.
 
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