Later model Hemi swap in a third generation Ram 2500 4x4

[Slick67cars]

I am new here so I appreciate any help I can get. I have a 2003 Ram 2500 quad cab 4x4 that has a Hemi and automatic transmission with overdrive. I am considering upgrading with a late model Hemi and transmission. My understanding is that I will need the engine harness and ecm from the donor vehicle in order for it to work. One of my questions is regarding transmission. Does the transmission need to come from a 4x4 truck or will a transmission from a car work? Also would I be able to use my existing transfer case or would I need to replace it with a late model unit? Thanks in advance for your help.

 

[HemiLonestar]

1. Neither of your gifs work.
2. No, you will not be able to retrofit a later model hemi without a standalone controller. CAN is required to run a VVT engine and it doesn't interface directly with PCI (which is the type bus you have). Also your fuel pump is about 10 psi too low.
3. Yes you can swap in the newer 4x4 trans but you will need a rather expensive retrofit harness, custom trans mount, electronic shifter (your stock column shifter will not work anymore) and likely have to alter the driveshafts to work.

 

[Slick67cars]

Some of this I don’t follow but thank you for responding.

 

[HemiLonestar]

Some of this I don’t follow but thank you for responding.

Well you'll never learn if you don't ask about what you don't understand, so ask what you need clarification on.

 

[Slick67cars]

I appreciate that but I will have to do that a little later in the day or this evening once I finish working. Thanks

 

[Slick67cars]

So what type of stand alone controller are you talking about? What does CAN and VVT refer to?

 

[HemiLonestar]

So what type of stand alone controller are you talking about? What does CAN and VVT refer to?

So your 2003 uses a communication protocol known colloquially as "PCI bus" (Programmable Communications Interface). This dictates the speed and type of communication between the different computer modules found in the truck. Even in 2003 there were quite a few. Starting in 2006 the 3rd gen Ram was updated to use CAN bus (Controller Area Network), which allowed for faster communication as well as more of it. While the 3rd gen hemi architecture had MDS designed into it from the beginning, it wasn't until the introduction of CAN that it could actually be used. In 2009 the CAN type was updated again to control VVT (Variable Valve Timing) for the 5.7 refresh (and eventual release of the 6.4).
PCI and CAN cannot directly interface without some kind of translator; if you are a computer or electrical engineer, then you have the skills to build one. Apparently it isn't a fun undertaking; there was an electrical engineer about 15+ years ago with an early Jeep Liberty (PCI bus) who wanted to use the new in 2008 MyGig head unit (strictly CAN). He built a signal translator and made it work; he could've started building these things for money (there were plenty enough people who wanted to buy them) but he didn't want to go through the process again.
Holley makes a standalone controller that will run a VVT hemi. It will even interface with the stock onboard gauge cluster. There is a 2004 quad cab running around Canadia with a 6.1 based stroker run by a Holley Terminator X with an 8HP70. In fact the owner is on here (or used to be).
Something else I haven't touched on is the fact that you will need to completely rearrange your accessory drive to use a later model VVT engine.

It's not a great fit because one change to accomodate leads to another change to accomodate and none of them are cheap lol.

 

[Slick67cars]

Thank you so much for your knowledge. Another question. What do you mean rearrange the accessory drive?

 

[HemiLonestar]

Thank you so much for your knowledge. Another question. What do you mean rearrange the accessory drive?

Accessory drive is the sum of components attached to the front end of your engine (hence why Mopar calls it 'FEAD' or Front End Accessory Drive) which includes alternator, a/c compressor, PS pump, etc. The hemi vehicles across the years from 2003 on all have very different specific setups due to packaging. 03-08 Rams are specific to those years. 09+ Rams are different due to both the engine redesign and vehicle update.

 

[Slick67cars]

Ok. Thank you