Tranny swap ?? 42rle to 45 rfe

f1paul · **Joined:** Mon Aug 22, 2005 10:38 pm **Posts:** 20

anyone ever hear of this being done ?
would love to get that 5-speed tranny from an '02 and put it in my '03, i hate the way mine shifts.
i would imagine all the mounts and brackets should all line up.

anyone with experience in this could ya please tell me what's involved to do something like this.

KY Liberty · **Joined:** Sat Jul 09, 2005 1:46 pm **Posts:** 1195

I think might be pretty difficult. The 3.7 with the 45rfe uses 2 seperate computers. The 3 harness ECU on the driver's side, and the TCM on the passenger's side. The 3.7 with the 42rle uses a 4 harness ECU with the TCM built into it. You'll need to talk to a good transmission mechanic that has lots of experience with both transmissions. Hope you have good luck with the swap. A 45rfe with a shift kit and upgraded torque converter will put the 42rle to shame.

unixxx · **Posted:** Tue Jan 30, 2007 11:17 am

To add to what KY Liberty said:

unixxx wrote:

There are two types of PCMs: JTEC and NGC. JTEC is the older controller and NGC is the newer controller. There's an easy way to tell the two apart: an NGC PCM has four connectors on it because it integrates the TMC (Transmission Control Module), while the JTEC has three connectors on it because it uses a seperate TCM.

Since all vehicles with the NGC PCM have an integrated TCM, unless you find a way to reprogram it, you're pretty much stuck with the transmission that originally came with the engine.

You might want to check out the last page of this thread:

http://www.lostjeeps.com/forum/phpBB3/vie ... php?t=4072

Boi1ermaker · **Joined:** Tue Jan 24, 2006 1:44 pm **Posts:** 249

Putting aside all the problems with trying this for a moment, if you are going to have to go thru the trouble of reprogramming anyway, is there a reason not to flash the 45rfe to a 545rfe and get the extra cruising gear?

Is it safe to assume swapping out the auto for a 5sp manual would have the same problems with controllers? (On top of the extra parts and labor involved with that type of swap)

KY Liberty · **Joined:** Sat Jul 09, 2005 1:46 pm **Posts:** 1195

So far everyone I've worked with has told me that this can't actually be done with the 3.7 and 45rfe. They've also told me that the 545rfe has some heavier duty parts in it and it is not physically identical. Just really close. I would love to hear from someone who actually can do it. So far, it's like the elusive 4.7 V8 Libby that wanders the hills of Pennsylvania that no one has ever been able to photo.

f1paul · **Joined:** Mon Aug 22, 2005 10:38 pm **Posts:** 20

thanks for the replies all you guys, i knew somebody would have the answer here.
I was really looking at doing this mod only if it was simple plug and play but it sounds like im out of luck.

i really do believe that this 42rle is a really junk unit, always searching for gears, shifting too early when foot is into it a little.and there is no shift kits available,nothing, for this tranny.
i washoping to go 5-speed auto and then order b&g flash....oh well, time to order flash as-is.

thanks for help guys

[/u]

unixxx · **Posted:** Fri Feb 09, 2007 12:58 am

Check out this thread for the new shift kit from Transgo for the 42RLE:

http://www.lostjeeps.com/forum/phpBB3/vie ... hp?t=17401

KY Liberty · **Joined:** Sat Jul 09, 2005 1:46 pm **Posts:** 1195

Get the new Transgo shift kit and a torque converter from APS. Combine that with a B&G flash and a Fastman throttle body. You'll have a completely different vehicle.

f1paul · **Joined:** Mon Aug 22, 2005 10:38 pm **Posts:** 20

looks like the timing for this shift kit is spot on.

it never works out like that. hehe.

hey kyliberty,that list of things is exactly what i am looking at doing, just curious, you think i should do the flash last so i can tell them about the other mods and they in turn can flash it more precise to work with them.

or is the flash pretty generic and have no relation to the other mods?

figured you would be the one to know

***never mind KY, just saw your performance mods thread, flash it first, got it, now to find a second computer from another '03 so no downtime***

KY Liberty · **Joined:** Sat Jul 09, 2005 1:46 pm **Posts:** 1195

I bought a spare PCM from Autocraft. Just make sure you get the VIN written to it, and get a dealership to program your keys to it. Otherwise it will only run for 2 seconds and die. Then make sure you reset the adaptives after each performance mod and let it relearn.

Jeepjeepster · **Posted:** Tue Feb 13, 2007 10:47 pm

What would it be like if I just got a shift kit and torque converter Ky? Who put yours in?

unixxx · **Posted:** Tue Feb 13, 2007 11:50 pm

KY Liberty, does Autocraft have a website? Is the below it?

http://www.autocraft.com/aeweb/app

KY Liberty · **Joined:** Sat Jul 09, 2005 1:46 pm **Posts:** 1195

That's not them. The used to have www.autocraftdirect.com, but that doesn't work anymore. The new site is:

http://www.worldautopartsdirect.com/

I just looked up my receipt from March 2005. I payed $250 for the computer for my '02, plus a $75 core charge since I wanted a spare and wasn't going to return my old one for a total of $325.

KY Liberty · **Joined:** Sat Jul 09, 2005 1:46 pm **Posts:** 1195

Jeepjeepster wrote:

What would it be like if I just got a shift kit and torque converter Ky? Who put yours in?

Mine didn't like the torque converter and 4.10 gears very much with the stock computer. I would highly recommend getting the B&G flash with it. I have Rusty at Cottman Transmission on Winchester Rd do all my transmission and differential work. He does a very good job.

unixxx · **Posted:** Wed Feb 14, 2007 1:32 pm

On their other site: http://www.transmissionscontrolunits.com , they show a 2005 Jeep Liberty TCM option where the 3.7L is paired with the 545RFE. Is this just a typo, or could I really buy a TCM from them that's programmed for a different engine/transmission combination?

KY Liberty · **Joined:** Sat Jul 09, 2005 1:46 pm **Posts:** 1195

unixxx wrote:

On their other site: http://www.transmissionscontrolunits.com , they show a 2005 Jeep Liberty TCM option where the 3.7L is paired with the 545RFE. Is this just a typo, or could I really buy a TCM from them that's programmed for a different engine/transmission combination?

Honestly, I have no idea on that. I would call them and discuss it. That's going to be a very costly and time consuming problem if you get the TCM and transmission and it doesn't work.

Tranny swap ?? 42rle to 45 rfe

Who is online