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Putting 4.7 V8 from 01 GC into 03 GC

10K views 59 replies 5 participants last post by  Gus9890 
#1 ·
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?
 
#28 ·
I have the whole front (radiator, bumper cover, etc.) removed on my donor car so that I can remove the engine, transmission, and transfer case as an assembly. I am going to do the same on the recipient car so I can remove the old engine and install the new one as an assembly as well.
 
#29 ·
Ok, I have not pulled the engine yet, but I have (I believe) almost completely finished removing everything to get ready, and I've got the chains and a load leveler attached to the engine. The last batch of stuff I disconnected was the driveshafts (front and rear), the electrical connections to the starter, the last plug on the transmission, the transfer case shifter, the transmission and motor mounts, a bracket on the passenger side of the transmission that supported part of the exhaust system, and the air conditioning hoses and condenser. I would have pulled it today, but instead I helped my son replace the tie rod ends, sleeves, track bar, and steering damper on his 92 Wrangler. FYI, I've done almost all that stuff on a WJ (except for the track bar), and the Wrangler was a hell of a lot easier to work on.

Anyway, the weather looks great for next weekend, so hopefully I will be pulling an engine then.
 
#30 ·
Pulled it!

Okay, we had some great weather, and I had some great help from a friend, and we got the engine out. Here are some issues that came up that I remember:

1. As others have posted on this topic, if you pull the engine/transmission/transfer case as an assembly, the tail end hangs low. We solved this by jacking up the rear as soon as the engine was clear of the cowl and running a tow strap from the end of the transfer case back up to the engine hoist hook point.

2. The exhaust crossover pipe kept being in the way. Numerous times, we had to wrestle the engine around to clear it. It was kind of crunched by the accident, this might explain it.

3. Since we were not removing the engine by itself, we could not lift the engine straight up, so the driver's side motor mount got in the way. I had to completely remove the motor mount from the engine, and I had to do it while the engine was suspended from the hoist, which was kind of scary.

4. I couldn't raise the engine high enough to clear the track bar because the throttle body was beneath the cowl, and the track bar was preventing the engine from being able to be pulled forward. I couldn't disconnect the driver's side of the track bar because the bolt was blocked by the bump stop. I spent some time cursing the engineers who designed the car before I realized that the whole area was deformed because of the accident. I ended up removing the passenger side of the track bar and that allowed it to drop out of the way.

5. One of the last electrical connections that needed to be removed was the crankshaft position sensor. At least, I think that's what it was; it was low on the passenger side towards the rear of the engine. The plug was very hard to get out.

6. It was kind of hard to get it set up on a dolly so I could unhook the engine hoist. I don't like the way it's supported right now; I'm going to have to do something about it.

Glad that's off my to do list! I'll post some pics tomorrow.
 
#31 ·
Pictures

Okay, here are some pictures I took with my phone while we were pulling it. The first one shows the wrecked Jeep with the engine hoist pulled up in front of it, attached to the engine. You can see the load leveler. The second and third pictures show how I hooked up the chains. I looped one over the two studs sticking up vertically out of the heads toward the rear of the engine, high enough to not crush the throttle body when the chains went taut. I read in a thread somewhere that you should use the nuts from the motor mount bolts on these studs, so that's what I did. They are flanged, so I installed them upside down because they seemed to nest into the chain better that way. I attached another chain to the stud sticking out horizontally from the front of the engine, then I attached the load leveler as you see.
 

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#32 ·
More pictures

Okay here are some more pictures. The first is a closeup that shows how the chains are attached to the vertical studs. This is important because this chain took virtually 100% of the combined weight of the engine, transmission, and transfer case. I was initially concerned that the chains would try to pull the studs toward each other as well as up, but I decided not to worry about it, and I saw no evidence during the lift that the horizontal component of the force was bending the studs, so that worked out okay.

In the second picture, you can see that the engine/transmission/transfer case (from here on referred to as ETTC) assembly is really tail heavy and wanted to droop in the back. You'll notice from the position of the load leveler that the looped chain on the vertical studs was taking nearly all the load. I think if you were just pulling the engine, the stud on the front would be useful, but with the weight of the whole ETTC, the only good it does is it gives you somewhere to grab to move the ETTC around while you try to get it out. I think next time I won't use the load leveler, which will give me more possible lift range on the engine hoist.

The third and fourth pictures show how we had to position it to get it out. Until we got the transfer case clear of the exhaust crossover pipe, the front axle, and all the steering and suspension parts, it helped to lift it on a tilt like that, so it comes out more or less straight up. However, the engine hoist did not have enough lift range to get the transfer case to clear the bumper support in the tilted position. So when we got it out as far as you see in the third and fourth pictures, where the oil pan was above the bumper support, we gently lowered it until it was resting on the bumper support, then we lowered it some more until the front of the ETTC dropped and the tail raised up, until the ETTC was horizontal. Then we attached a tow strap (we could have used another chain) between the hoist hook and the transfer case to maintain the horizontal position. Then we raised the ETTC until the oil pan was off the bumper bracket, and slid the hoist with the engine on it away from the car. (We actually tried attaching the tow strap to the transfer case before we got it into the horizontal position, but it didn't do any good, so we readjusted it after we got it into the horizontal position, but when I do this again, because I will have to do this again, twice as a matter of fact, once to get the blown engine out and once to install the good engine, I will do it as I described above.)

The fifth and six pictures show the engine on the driveway in front of the car, and then inside my garage, on cheap Harbor Freight furniture dollies, that will barely roll on their tiny plastic wheels when they have the weight of an engine on them. But they are great for the price.
 

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#34 ·
Re: Easier to remove tranny and t-case first?

I don't really know the answer to that question. Considering that I want to use the entire drivetrain from the donor vehicle, not just the engine, I never seriously thought through for myself how much work it would be to separate the engine from the transmission, and based on what I have read on forums and what a real mechanic told me, it's a very tough job while the drivetrain is in the vehicle, so I just ruled it out as an option. The mechanic said that you have to have all the wobble sockets, u-joint socket adapters, extensions, etc., that they make, and even then the way the engine is positioned so far back into the engine compartment, under the cowl, makes it really difficult to get to those bolts. I have only swapped one other engine in my life, from a 1973 Dodge Charger with a 318, and I just did the engine, and I always regretted that I didn't just pull the whole drivetrain, because in hindsight I think it would have been easier. (I also replaced a transmission by itself, in a 1973 Plymouth 'Cuda, and that was way harder than pulling an engine, and I wished even more during that nightmare that I had just pulled the whole drivetrain.)

Considering the pros and cons, the major con to keeping the drivetrain together is that you have to remove the bumper, radiator, A/C condensor, etc. from the front of the vehicle to make room. However, I have done that before and I know how to do it. It takes some time but it's actually kind of simple. Plus, the bumper cover on my recipient vehicle is cracked (the entire driver's side fog lamp is broken off), and as it turns out the front bumper cover from my donor vehicle, while the wrong color, is still intact, because it was removed before the wreck to make room for an aftermarket bumper. If I coordinate this right, I might be able to get that painted and put onto the vehicle as part of the engine swap.

Plus another thing is that I plan to pull the busted drivetrain out with the wiring harness still attached - it is attached to both the engine and transmission - and then move the harness over to the new drivetrain before installing it. That will mean less work to get the new drivetrain hooked up and running after installation, and the work I will be avoiding includes a lot of laying on the ground or reaching into corners, blind, trying to plug stuff in, which I hate.

I'm not saying I'm completely right, it's just that I'm satisfied in how I'm doing it. In other situations, for people with different levels of expertise and experience (i.e., people who are less ignorant then I am), it might have made sense to do it a different way. I'm interested in hearing the opinions of others on this topic.
 
#35 ·
I never changed the engine on my WJ, but did the tranny and T-case last year. Not that difficult and i didn't use any special spanner or socket to get the job done. You only need a good lifting platform to support the weight of the tranny, which is around 70-80 kg and the jeep has to be from the ground, to create space to remove the tranny from under it. If you would only remove it and install on the other engine, you could just simply let it stay under the jeep.
 
#36 ·
My main concerns about replacing the engine only would be

1. Getting to the bolts that connect the transmission to the engine near the top of the engine, tucked way back under the cowl, behind the throttle, and

2. Disconnecting the torque converter.

How hard were these two things when you did it? If I could be convinced that neither one of those two were that hard, I might do the engine only.
 
#37 ·
Update and spark plug advice

I thought I would update my progress. I am going forward with the entire drivetrain swap with the wiring harness in place. This past weekend, I disconnected almost everything that needed to be disconnected from the drivetrain, including the driveshafts, the exhaust system, and the front bumper, headlights, and associated paraphernalia. The biggest thing I have left to do is removing the radiator/fan/condenser from the front of the Jeep.

I did discover a minor hiccup: the 03 engine intake manifold has a plastic flange molded into it that retains the throttle cables, whereas the 01 engine that I am putting in it has a steel plate that bolts to the intake manifold that holds the throttle cables. If I can't figure out how to get the throttle cables from the 03 Jeep to mount to the plate from the 01, I will have to swap the intake manifolds.

Also, and I might start a separate thread about this, I want to change the spark plugs while the engine is out, and I'm looking for suggestions. I have heard the iridium spark plugs are the best, but I don't know what brand to buy. I think the OEM is Denso, so I'm leaning that way, but I've also heard NGKs are really good.
 
#38 · (Edited)
Disconnecting the torque converter is very easy. You remove first the structural cover on the bottom side between engine and transmission (6 bolts i believe). Now you look at the rear side of the flex plate where you can remove 1 bolt at a time, which hold the torque converter to the flexplate (total of 4 bolts). You remove the first bolt and then have to rotate the crankshaft to get access to the next bolt.
The lower transmission to engine mounting bolts are easy to remove, but for the upper ones you have to lower the rear side of the engine as far as possible, so that you can get to the upper bolts through the transmission tunnel, on top of the transmission. if you remove the torque converter, you will have to change the torque converter shaft o-ring as well.
Don´t know how long it took for you to take the whole assy out and if it all worked without damaging components/wiring/etc. Taking the T-case off and then the tranny took me at least 6 hours, laying on the ground most part of it.
Attached some pics of the torque converter with the 4 mounting bolt holes and the space above the tranny with the engine aft side lowered as far as possible.
O, and the OEM plugs are champion copper cores. I did run Bosch with no alterations.
 

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#39 ·
Your torque converter looks quite beautiful poised on your dining room table next to a platter of fruit. I'm sure your wife was thrilled! (Maybe she hasn't seen this picture, or maybe you don't have a wife, although your dining room table looks too clean for that.)

Actually, it took about 2 hours to get the engine/transmission/transfer case out of the car, but that time was preceded by hours and hours of work disconnecting and unplugging everything, spread over several weekends. I did damage at least one 02 sensor bringing the engine out. I also had to disconnect one end of the track bar to get the engine out, and I had to not only disconnect the motor mounts, but remove the bracket mounted to the body that the motor mount connects to.

Now that I know what I'm doing, I basically whipped through most of the physical disconnections in about 3 hours last weekend. I plan to do very little electrical unplugging this time, because I am going to leave the wiring harness in place. I am so confident of being able to do this relatively quickly that I am planning on yanking out the blown drivetrain assembly and installing the other one on the same day (Saturday April 20th). We'll see how that goes.
 
#40 ·
Yeh, the torque converter is a new (rebuild) one. When i would have put the old one on there, for sure it would have given some fights with my wife:slapfight::D.
Didn´t show her this picture as well, just to not awake a sleeping dog:lol:.
Good luck with the engine swap.
 
#41 ·
Ok, so I did the drivetrain swap on Saturday as I had planned. It was not easy: my friend and I pulled out the entire blown drivetrain from the 03, then we did some work on the good 01 engine (replaced spark plugs, camshaft and crankshaft position sensors, and motor mounts). Then we put the 01 wiring harness back onto the 01 engine, and dropped it in.

At the very end, we were plugging all the harness connections back in, and there was one problem. Near the PCM and TCM, there was a female plug attached to the 03 body wiring harness with 4 wires coming out of it. The only remaining plug in the 01 engine wiring harness to match it with was also a female, with only two wires coming out of it. See the pictures below. The left picture shows the 03 body plug on the left and the 01 wiring harness plug on the right. The second picture is the back of the 03 body plug, showing the 4 wires coming out. The third picture is the 01 body plug, showing the 2 wires coming out. It's hard to see in the pictures, but one of the wires in each of the harnesses appears to be the same color (purple with a dark stripe).

So I'm super unhappy with myself for not using the 03 harness. Part of why I did it was that I wanted to preserve the routing of the harness on the blown 03 engine as a reference for when I was hooking up the other harness. Another part was that I was convinced that they were identical, because they were both JTEC and had the same VIN number except for the year and the serial number of the vehicle. I also was thinking that the 03 harness might be in worse shape because it came from a 190,000 plus mile vehicle. I guess I made a bad decision, and now I think I will have to swap harnesses after the engine is in the vehicle, when it's hard.

There's a chance that I can figure out what these wires are for and splice the 03 plug into the 01 harness. All I lack to be able to do that is the knowledge of what those wires do. Can anyone help with this?

If it helps, the plugs had numbers on them, as follows:

01 plug: 07329-C (top row), 2830-36 (bottom row)

03 plug: 07310-F (top row), 3130-53 (bottom row)

The interweb hasn't been of any help with these numbers.
 

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#42 · (Edited)
I had a look at my jeep when i came home. The connector you are talking about seems to be the C104. There are two types according the wiring schematics, one with two wires (Violet/white stripe? and Violet/orange stripe), which seems to be the one from the 01 harness.
The other one is for a HO engine and has 6 wires, maybe the two extra wires for the knock sensors? Attached some pics of the position and connector pinout. Still looking where those wires are for. Will come back.
 

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#43 · (Edited)
What i found sofar regarding the C104 with the two wires:
Cavity 1 = wire K200 18 VT/OR (violet/orange stripe). This is voltage supply for the oxygen sensor heaters.
Cavity 2 = wire K6 18 VT/WT (Violet/White stripe). It is also shown as K6 18 VT/BK (violet/Black stripe). This is the 5V supply voltage from the PCM to the AC pressure transducer.

Can you have another look at the wires which exact color code they have?
Just found out that for the C104 with the 6 wires, 4 wires are for the knock sensors. The remaining two are the same as the two wire connector.
So what are those two extra wires on yours doing? I have the manual 99-00 and 01-04 and they are different from each other and i saw that my 04 jeep is also not the same as the schematic:confused:
 
#44 ·
Ok, this is some great information. Here are some more details:

1. The plug that is on the engine harness, from the 01, looks like the C104 plug shown on page 8W-80-11 of what you sent me, the one that is labeled 4.7 L in parentheses. The positions of the wires are as follows:

Position 1: Purple with orange stripe
Position 2: Purple with black stripe.

2. The plug that is on the body harness, on the 03, looks like the C104 plug shown on page 8W-80-12, labeled High Output in parentheses. The positions of the wires are as follows:

Position 2: brown with orange stripe
Position 7: brown with white stripe
Position 8: blue (no stripe)
Position 9: Purple with black stripe (a possible match!)

I'm nearly 100% positive that the 03 did not have a HO engine in it, based on the VIN numbers. Also, although my 03 body has a 10 position plug, like the one that's labeled "High Output" on page 8W-80-12, it only has 4 wires in it, unlike what's shown on page 8W-80-12, which has 6 wires.
 
#45 ·
My 04 WJ with 4.7 also has the 10 pin plug, it has 4 wires on the engine side of the connector, but i believe i saw 8 wires on the body side of it.
The HO engine has 6 wires on the engine side of the connector, but 4 of them are for the two knock sensors. The other two are the violet/orange and the violet/black, so in fact the same two wires as your 01 has.
Lets see if we can find the other two wires in the connector.
 
#47 · (Edited)
Would not expect because of the colour of the wires. Can´t find a wiring schematic for the 2003 only, do you have it?
If you track down the wiring ends of the bundles, do you see the two wires somewhere?
 
#50 ·
Okay, so I just swapped the wiring harness. I had to disconnect the transmission cross member and lower the transmission/transfer case to make room to slide the thick bundle of wire between the top of the throttle body and the cowl, and I had to remove the starter to get to the crankshaft position sensor. What a messy, knuckle-busting, frustrating pain in the a**. It took me about 3 1/2 hours. It would have been 3 1/2 minutes if I had done it with the engine out of the car. Oh well.
 
#51 ·
And I made an extremely boneheaded mistake which I now have to fix. After I got the harness in place and all plugged in, I was raising the transmission/transfer case back into place so I could reattach the transmission cross member, then I was going to work on reconnecting the exhaust system. There is an exhaust hanger bolted to the passenger side of the transmission. Mine was loose, and as I was jacking up the crossmember, somehow the hanger got wedged up against the transmission oil pressure sensor (generic picture attached) and broke it off. The end of it is still in the transmission (everything from the outer blue O-ring to the very tip). I don't know how I'm going to get it out. It's got a hole in the middle, so theoretically I could use a drywall screw or an easy-out, but I'm afraid I might push it all the way in and never find it again. Goodbye transmission.

One possibility is if it's accessible from inside the transmission, I could drop the pan and fish it out from there. Looking on the bright side, this gives me a chance to replace the filter and fluid, which I wanted to do anyway. Frango, you seem to be the only one who's reading this thread, and you recently replaced your transmission. Do you know if the sensor tip is accessible from inside the transmission pan area?
 

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#52 ·
I was looking at auto parts web sites to find out who stocks transmission filters and how much they cost and some of them show an external filter that looks kind of like an oil filter. Where would this be located? How do I know if I have one or not?
 
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