V8 Wiring and computer Swap for a 4.7L?

Christopher · **Posted:** Wed Dec 05, 2007 10:00 pm

Why would you swap the tranny? the 45rfe will bolt up to the 4.7.

jb4204562 · **Joined:** Tue Oct 23, 2007 10:14 pm **Posts:** 64

I didn't know until just now that they used this auto trans with the 4.7L powertech motor in the grand cherokee as well. Soooo I'm guessing the computer that I get from the donor car will work with my existing transmission... is there anything different between the two(GC or Libby)?????

ARBSeth · **Posted:** Thu Dec 06, 2007 1:42 am

Hey Guys,

Jordan fron AEV gave me tons of information about what I'd need to make it work.
Problem is I'm not 100% sure it would pass WA state emission laws. So until I have another rig to drive (Buying a Rover this weekend) I'm not cutting Ole Girl up AGAIN just yet.

Here's what I need...

02 WJ Wiring Harness, Computer and the 4.7... The tranny will probably come from the donor truck, alothough my existing one will work. Mine has 150K on it now, it needs a new one! I'm also building a new front axle because the D30 I used for the SFA swap is too little to handle to abuse I'm going to throw at it with a new V8. More cash to spend... anyone want a HPD30 with 4:56's, 30 spline 4340 shafts, Vanco Dics and of course an ARB Air Locker? Anyway...will also need a complete new exhaust system including headers and a new Cat. More cash... I'm going broke on a truck that isn't worth $9000!!!

When I have some time, I'll drop the POS 3.7 off at the Yard and get started. Hang in there... good things to come.

Seth out.

unixxx · **Posted:** Thu Dec 06, 2007 2:42 am

Seth, what made you choose 02 WJ components over those from an 03 or 04, which also use the PCI bus?

jb4204562 · **Joined:** Tue Oct 23, 2007 10:14 pm **Posts:** 64

hmmmmm, i might have to look into the emissions laws here in NY..... Seth, do you have contact info for Jordan at AEV or can you forward me the info that he has shared with you??? my engine blew after 180,000 miles,.... and i'm most definitely looking into getting this done. I'm going to be dealing with tntconversions to get the SFA going.. and figure if I can do it I might as well go through with the V8 swap while i'm at it...

Guest · **Posted:** Thu Dec 06, 2007 1:45 pm

unixxx wrote:

Seth, what made you choose 02 WJ components over those from an 03 or 04, which also use the PCI bus?

'03-4 Grand Cherokees have the combination TCM and ECM. '99-02 uses the seperate computers.

jb4204562 · **Joined:** Tue Oct 23, 2007 10:14 pm **Posts:** 64

Looks like I can get the harness and computer from an 02 WJ that was 4x4 and had the 45RFE AT for about 400 dollars. The engine is about 1900... and now I just need to know if I could use the same transfer case or would I need that from the WJ as well?? Oh yea and would it make a difference for emissions if the computer came from a truck in California??

Guest · **Posted:** Thu Dec 06, 2007 3:10 pm

jb4204562 wrote:

Looks like I can get the harness and computer from an 02 WJ that was 4x4 and had the 45RFE AT for about 400 dollars. The engine is about 1900... and now I just need to know if I could use the same transfer case or would I need that from the WJ as well?? Oh yea and would it make a difference for emissions if the computer came from a truck in California??

Your t-case will be fine. The WJs did not have command-trac, only Selec-trac & Quadra-trac. Keeping your T-case is good anyway, the output shaft for the KJ is 32 spline, & the WJ is 27. the input shaft on the t-case is the same for KJ & WJ so there should be no problem using your KJ t-case.

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

jb4204562 wrote:

Looks like I can get the harness and computer from an 02 WJ that was 4x4 and had the 45RFE AT for about 400 dollars. The engine is about 1900... and now I just need to know if I could use the same transfer case or would I need that from the WJ as well?? Oh yea and would it make a difference for emissions if the computer came from a truck in California??

If the computer is from Califonia, it's probably programmed for lower emmissions and lower power. Also, you have to get your VIN written to the PCM or the motor will shut down after a few seconds. You're going to need to call B&G. They make 5.7 and 6.1 Hemi conversion flashes, and upgrade flashes for most of the lineup of DC's motors.

Edit:
Also call up APS and talk to Wayne about an upgraded torque converter with the correct stall for what you're building and get the better of the 2 shift kits for the 45RFE while you're at it too.

unixxx · **Posted:** Fri Dec 07, 2007 4:18 am

Why does Seth need a JTEC PCM w/ separate TCM over an NGC PCM w/ integrated TCM?

ThunderbirdJunkie wrote:

unixxx wrote:

Seth, what made you choose 02 WJ components over those from an 03 or 04, which also use the PCI bus?

'03-4 Grand Cherokees have the combination TCM and ECM. '99-02 uses the seperate computers.

csukoh78 · **Joined:** Thu Mar 08, 2007 10:34 pm **Posts:** 501

man this is going to be cool

C co Crusader 2/127 · **Posted:** Fri Dec 07, 2007 12:57 pm

hey seth if whats the current condition of the 3.7 you have now? I mean i know it has a ton of miles but if its rebuildable why not trya nd sell it or give it away to someone that would like to try and make a go out of built up 3.7 with a turbo or supercharger. Id take it off your hands in a heartbeat but at the moment i have no space and im not driving to washington to pick it up right now. Anyway thats just a sugestion; the more people we have working on options for the lib the better. An I know what you mean about the worth of the vehicle. I have maint. recors on mine all the way down to swales slips for leather cleaner and car was soap. I took it in because i was going to trade it for a JK and the dealer offered me 9k for it!!! I just got up and walked out when he told me that.

Guest · **Posted:** Fri Dec 07, 2007 10:48 pm

unixxx wrote:

Why does Seth need a JTEC PCM w/ separate TCM over an NGC PCM w/ integrated TCM?

ThunderbirdJunkie wrote:

unixxx wrote:

Seth, what made you choose 02 WJ components over those from an 03 or 04, which also use the PCI bus?

'03-4 Grand Cherokees have the combination TCM and ECM. '99-02 uses the seperate computers.

I forgot he was going aftermarket with the ECM and such. Myself, I'd just swap the 4.7 in as-is, stock, wtih the stock harnesses and stock modules.

jb4204562 · **Joined:** Tue Oct 23, 2007 10:14 pm **Posts:** 64

I was thinking about this last night and I'm thinking that I could probably just use the 02 computer for a WJ with the engine, harness, and fuse box, modules, etc... and just ditch the computer in the car now... just kinda make the computer think it's still in a WJ, get the pin outs and just tie in all of my accessories to that computer. like the sensors, power windows and door locks, windshield wipers, lights, etc... the computer that I'm getting is coming from a 4x4 with the 45RFE transmission, so that wouldn't be any different... and the transfer case should work as well because it is a selec trac....

jb4204562 · **Joined:** Tue Oct 23, 2007 10:14 pm **Posts:** 64

So here's where I stand...... the guy at the shop that is going to be doing the SFA swap on my truck... just so happens to have a relative that works for and is an enthusiast for Jeep.... he is looking into this for me now and I will have an answer soon as to how possible it is to make my car a turn key V8...... I just secured the engine(complete and running), computer, harness, and fuse box for just a bit more than 1900 dollars! This is all happening very fast now.... I can't wait to get more answers in an hour or so... I'll keep you posted! check the SFA board for pics of the work that these guys do! I'm almost positive this will be a success....

jb4204562 · **Joined:** Tue Oct 23, 2007 10:14 pm **Posts:** 64

Seth?

V8 Wiring and computer Swap for a 4.7L?

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