I have a 2002 3.9 V6. I want to put a 4.7 in. There's a guy on eBay who has a 4.7 but it's a 2008 Dakota. Would his engine fit my truck? He's offering to sell me the whole truck so I could use it for parts if I had to.

 

4.7 is a different design and wont fit without some fab.

Another 3.9, 5.2, or 5.9 would work but keep in mind you'll need a pcm and new writing harness unless you splice in 2 extra fuel injectors.

Also your tranny is the 42re which was never behind the 4.7. Won't bolt up.

 

He's offering the whole truck to me in case I need the parts. Would I be able to use his transmission too? I know there'd be some fab involved.

 

Yeah its definitely doable but a big project.

Keep in mind you'll most likely need new driveshafts too...

If I were you I would just find a 3.9, 5.2 or 5.9. Much less work involved.

 

if your getting the complete truck and can use it as a donor I'd do it in a heart beat especially if doing fab work isn't much of a problem

 

Doing fab work is always a problem. Always seems like fab work is done on my back, lying under whatever I'm working on, with oil, dirt, or sparks trying to get in my eyes, ears, nose, and throat.

It'll take electrical figuring, motor mount adapting, drivelines, custom trannie cross member, exhaust work, probably fuel system work, a/c fiddling, and then it won't be automatically right. The risk for FUBAR is extremely high. For all that BS, I'd rather have a 5.9. Probably, tho, I'd just dump it and get a truck I like. If it has to be a Dakota, maybe an R/S?

KIS,S! (keep it simple, stupid) (Not calling anyone stupid, here, btw.)

 

A few other things to deal with - still not insurmountable but to be considered:

1. The '08 Dakota should be drive by wire - no throttle cable. You'll need a throttle body setup, and possibly and intake manifold, to make it work. This won't come from your "parts" truck.

2. The PCM. You can forget completely about using it from the '08 as it would be CANBUS. The rest of your truck just isn't compatible electrically - as in gauges, ABS, etc.

3. Tone Rings in the engine. Dodge started changing from JTEC to NGC PCM's in '02. If you have 3 connectors on the PCM (JTEC - 16 teeth) on the '02, you'll need to change tone rings to the older style.

The NGC PCM uses 32 teeth and they are not compatible.

 

something else to look at too. the 5.2 and 5.9 will have more options to build up.