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-   -   Putting 4.7 V8 from 01 GC into 03 GC (http://www.jeepgarage.org/f204/putting-4-7-v8-from-01-gc-into-03-gc-54747.html)

mantonas 02-13-2013 09:41 PM

Putting 4.7 V8 from 01 GC into 03 GC
 
I have a wrecked 01 Grand Cherokee with a perfectly good 4.7 V8, and I am soon to acquire a nice 03 Grand Cherokee with a bad engine, and I am going to put the engine from the 01 into the 03. They are both Limiteds with Quadra-Drive. Until today I didn't think I was going to have any problems with interchangeability, but somebody at work got me thinking that there might be differences between these two years in the engine management systems. Sure enough, poking around on this forum, it turns out there are two different ones, JTech and NGC, and the 2003 might have either. Does anyone have experience with this situation? I have the VIN numbers for both vehicles, can you tell which engine management system it has from the VIN?

Frango100 02-13-2013 09:53 PM

Re: Putting 4.7 V8 from 01 GC into 03 GC
 
Canīt help you out with the VIN number, but indeed there can be a difference in the tone wheels of these engines. One uses a 16 teeth tonewheel, while the other uses a 32 teeth wheel. The JTech has a separate PCM and TCM, while the NGC has one controller where all PCM and TCM functions are inside one box.
My jeep (a WG though) is from 2004, but still is JTech.

mantonas 02-13-2013 10:23 PM

Re: Putting 4.7 V8 from 01 GC into 03 GC
 
If they're both JTech, and both non-HO, does that mean it's a straight drop-in swap? Based on the VIN numbers, I can at least tell that they're both non-HO.

Frango100 02-13-2013 10:30 PM

Re: Putting 4.7 V8 from 01 GC into 03 GC
 
As far as i know there should be no problem in swapping when both are JTech and non HO. Just keep the PCM with the jeep it was in, otherwise the PCM has to be programmed with the new VIN.

mantonas 02-13-2013 11:18 PM

Re: Putting 4.7 V8 from 01 GC into 03 GC
 
1 Attachment(s)
And a surefire way to tell whether you have JTech vs NGC is the separate transmission control module (TCM) next to the coolant reservoir, like in the middle of the attached picture from my wrecked 01 that will be the engine donor. If it has one, it's JTech. Right? So I just need to look under the hood of the 03 that I will be putting the engine into, and if it's also got the separate TCM, and it's non-HO (which it is, based on the VIN number), then it's smoooooth sailing.

Frango100 02-14-2013 02:21 PM

Re: Putting 4.7 V8 from 01 GC into 03 GC
 
Yes, when it has the separate TCM its the JTech.

mantonas 02-15-2013 10:56 AM

Re: Putting 4.7 V8 from 01 GC into 03 GC
 
1 Attachment(s)
All right, here's a picture from my wrecked 01 GC that will donate the engine:

mantonas 02-15-2013 10:58 AM

Re: Putting 4.7 V8 from 01 GC into 03 GC
 
1 Attachment(s)
And here's a picture from under the hood of the 03 GC that will receive the engine from the 01:

mantonas 02-15-2013 10:58 AM

Re: Putting 4.7 V8 from 01 GC into 03 GC
 
So it looks like both are JTech and I am good to go.

mantonas 02-16-2013 05:08 PM

I bought it!
 
Based on the fact that I know the engines will interchange, I closed the deal on the 03 GC. It's now sitting in my driveway next to the wrecked 01 GC. Today, I removed the radiator assembly from the 01 and put it on jack stands, then I just spent a lot of time looking at it to figure out what all needs to be disconnected. Then it got really cold and I quit for the day.

Hopefully tomorrow I will get out there and start removing the transmission cross member, the shifter linkages, the exhaust system, the engine mounts and the fuel line. Then all I have to do is unplug the various sensors and take it out. Very soon I hope to have the engine/transmission/transfer case assembly out and sitting on the floor of my garage.

Any tidbits of knowledge that others have obtained in the course of doing something like this would be greatly appreciated.

I am both nervous and excited.

mantonas 02-21-2013 12:56 PM

Re: Putting 4.7 V8 from 01 GC into 03 GC
 
All right, I've hit my first bump. I need to disconnect the exhaust pipes from the exhaust manifolds. It's got the typical impossible-to-remove rusted-on exhaust system bolt problem, just like any car, compounded by a lack of access. I don't care about the exhaust system in the car I'm removing it from, so I could just cut through the pipes close enough to the engine so they don't interfere with taking it out, but I'm going to have the same problem in the car that I'm putting it in, and I don't necessarily want to destroy that car's exhaust system. Any suggestions? Or is this just a good time to put in a new Y-pipe? I haven't checked prices on that yet . . . .

mantonas 02-21-2013 12:58 PM

Re: Putting 4.7 V8 from 01 GC into 03 GC
 
Ok, I just checked, it's $350. Damn.


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