New Hampshire's Original Diesel Performance and Repair Specialists



Scott's Cummins M998

As if an Ex-Millitary M998 Humvee isn't already cool enough, Scott had the idea of putting in a Cummins.  This has been done before but this one is a little cooler than the typical one.  Instead of the simple and generic 12 Valve swap this 6.2 is being replaced by a 5.9L Common rail motor out of a 2006 Ram.

The Build

All Motor Swaps are a Puzzle, just sometimes you have to make the pieces yourself

An Idea is Born

Scott Came to us with his beautiful M998 Humvee and explained what he wanted to transform it into, the Humvee was great but with its 3l80 transmission and its non- turbo 6.2L GM Diesel Motor it was just not suited for much road driving.  He had already purchased a doner truck, a 2006 Dodge Ram 2500 Cummins.  He wanted to keep the Humvee a Humvee but wanted it to have more power and be more suited to drive around on the road.

Disassembling the parts truck 

The first step of this build was removing the Engine, Transmission, Engine wiring harness, and Body wiring Harness from the donor truck.  With the engine being a 2006 it is controlled by computer and the throttle is controlled by and electric petal so it was nessacary to remove the full body harness to control the engine.

Simplifying the Harness

The modern 2006 Dodge had many creature comforts that a Humvee doesn't and these were all connected to the body and engine harness.  things such as the radio, a/c controls, air bags, and many other modern amenity's had to be removed from the harness.  One of our techs removed all of these by removing the pins from the connectors in the harness to make it look as though they had never been there.

Preparing to remove the 6.2  

It was time to tear down the M998 and that started with removing the front cowl.

With the 6.2 being set so far back in the chassis we had to prep the body to be lifted

Because of the motor sitting almost completely under the body and the rest of the drivetrain being tucked into the body for high clearance we had to lift the body off the frame to go any further, to do this the fuel tank and exhaust had to be removed.

Body is finally off!

With all the wiring, steering shaft, and other lines disconnected the body could finally be separated from the frame.

Removing the 6.2

Because of how far back the motor is set and how high it had to come to clear the air lift hooks a conventional motor crane just wasn't the right tool for the job .  Good thing we are prepared for these situations 

Positioning the Cummins

With the Cummins being a straight 6 apposed to the V8 it is much taller and longer than what was designed to be in the M998, No room for the massive stock fan of the Cummins motor.  With no fan in the way we were able to bring the motor forward to help with the added length.

Making Motor Mounts

With the Cummins where it needs to be we were able to make new motor mounts

Now was time for the 48RE and NP241

The 3l80 had to go, it wasn't suited for the power of the Cummins and 3 speeds just isn't enough to comfortably drive on the road.  So in comes the 48RE from the Dodge.  Well the AWD NP218 is great for off-road and combat situations,  it is not needed on the road, that being said the 4x4 capabilities of a Humvee are what makes it a Humvee so in goes an NP241 transferase to make it 2wd/4wd.