Swapped a 1996 2wd 3500 to a 1999 4x4 3500 frame.

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aphin

Junior Member
Joined
Jan 21, 2024
Posts
2
Reaction score
3
Location
Virginia
Ram Year
1996
Engine
12v Cummins
Hey y’all, first time poster, but I’ve learned so much reading forums and wanted to share my experience with my latest project. For a little background, about 8 years ago I bought a 2wd 1996 Ram 3500 dually with a 12 valve Cummins, a 47re, and geared at 3.54, at about 180k miles. At 261k miles I rebuilt the engine with a friend, no crazy upgrades. This past summer I swapped out the 47re with a NV4500. At some point I added a front hitch and 12k winch, which, when asked why, I always joked that it’s a 2wd dually that always get stuck. After realizing that my life has brought me back from Virginia to the family homestead in Vermont to help on the maple syrup farm, I quickly learned that I’m going to need a 4x4 rig.

I found a 4wd 1999 Dodge 3500 with the same extended cab and long bed setup as my own truck that was being sold for $3500 without the motor. This truck came with a NV4500 and transfer case, so I drove 500 miles, loaded it up, and towed it home to be my donor truck. The frame was solid, but the interior was shot.

Now, this whole project happened in the driveway with basic tools. A 3 ton floor jack, a 2 ton engine hoist, a socket set, an 18 volt 1/2” impact driver, a 250lb torque wrench, ratchet straps, and a chain fall. You get the idea.

The first thing I did was push the truck under a tree and hoist the bed off using a chain fall and large tree limb. Next, I used the floor jack and engine hoist to start lifting the cab, building it up on cinder blocks until it was 5 blocks high and I could roll the frame out from underneath it. Yes, I know, I’ve done more sane things but don’t recall when. I stripped the frame of the wiring harness, dropped the fuel tank, cleaned the surface rust and painted it. Keeping in mind that I was going to put a 1996 cab on a 1999 frame, I had no doubt that the wiring harness to the rear of the frame would not be compatible.

Next, I removed the batteries and disconnected all the wires from the 1996 12 valve motor, the reverse light switch on the NV4500, and the two wiring harnesses for the wires that go to the back of the frame. I also disconnected the parking brake cable, and unbolted the brake lines at the block behind the front left wheel. I removed the radiator, intercooler, and upper front cross member. I disconnected the steering shaft, throttle cable and cruise cable, and heater core hoses. Inside the cab, I removed the stick shift.

After everything on the frame was free from everything on the cab, I used the same process of lifting that cab. I had the engine hoist hooked to two axle straps with shackles attached at the front corners of the firewall, and the floor jack at the rear of the cab, moving it from side to side as I inched and blocked it upwards. Once it was high enough, I rolled my 2wd frame out.

At this point, I was able to easily pull the motor and transfer it to the 1999 4wd frame. I also transferred the wiring harness to the rear of the frame, the fuel lines, and fuel tank (I used the FASS 150 from the 1999 as a transfer pump to drain the tank). Because the rear axle ABS sensor is different between those years (which I learned when I dropped a 1998 NV4500 in earlier and no longer had a working speedometer. I now use Dakota Digital GPS for that) I swapped out the ABS sensor.

Now, here’s where the only thing during this whole project didn’t work out. The 1999 has four wheel ABS, with the front brake lines running separate of each other. My only expense (had I just down a 1 for 1 swap) other than antifreeze, oil, and trans fluid, was an 8” piece of brake line and a coupling to join the to front brake lines back into one at the blocks behind the front left wheel. That was it.

After joining my 12 valve to the NV4500 and dropping it back into the motor mounts, running the fuel lines down the frame (I only detached them at the tank for this whole process), running the 1996 wiring harness to the back of the frame, and mounting the fuel tank, I was ready to roll that chassis under the cab and start the slow process of lowering it back down. I got the 1996 cab bolted to the 1999 frame using the 1996 rubber mounting hardware without any issues. I reconnected all the wires under the hood, reconnected the brake lines, steering, radiator, intercooler, everything…

Following that, I returned to the donor truck and removed the 4wd handle from the cab floor. It easily unbolted with a couple nuts under the cab and a bolt on the inside. Luckily, I found that there were dimples in the floor of my 1996 cab for the two main bolts in that assembly, so with some basic measurements I was able to cut out a small rectangle for the 4wd shifter to go through the floor and connect to the transfer case.

After refilling the antifreeze, doing an oil change, and replacing both the transmission and transfer case fluids, refilling the power steering reservoir, bleeding the brakes, replacing the fuel filter, and priming the diesel, I was ready to fire the truck up.

My purchase list to this point follows:
4wd donor truck
6 gallons antifreeze
3 gallons oil
5 quarts GL-4 trans fluid
2 quarts ATF-4 trans fluid
1 quart power steering fluid
2 quarts brake fluid
Oil filter
Fuel filter

Now, all of that went well and I could have stopped there, but I didn’t. After buying the donor truck, I realized it had 4.10 gears. Because I drive 2200+ miles a month, I decided to swap my original rear axle back under the truck, and found a 1997 front axle (400 miles away) that was geared for 3.54. I also decided to replace the steering system, front wheel bearing hubs, calipers, and rotors. I also replaced the gear oil in both axles at this point. This part of the project took as long as the whole frame swap and was not cheap and I had to cut the sway bar mounting points out of the 1999 front axle and weld them into the 1997 axle to make the sway bar work. I ended up removing the rear sway bar because the 1996 2wd rear axle brackets were not compatible with the sway bar brackets on the 1999 4x4 axle.

I have recouped some of my money be selling the NV4500, the 5” exhaust that was on the donor truck, both 4.10 axles, and the fresh mud tires from the donor truck. This entire project cost me about $6,000 and I was able to get about $4,000 back from selling parts. Had I not done the axle swaps and rebuilt the steering, I would have turned a profit.

Hopefully this write-up helps someone along the way. As I said earlier, these forums have been lifesavers for me and it’s only right to share my experience with such an extensive undertaking.
 

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aphin

Junior Member
Joined
Jan 21, 2024
Posts
2
Reaction score
3
Location
Virginia
Ram Year
1996
Engine
12v Cummins
One piece of additional information, I took the 1999 cab to the scrapyard and learned that it weighed just over 1,500 pounds. That’s something to keep in mind if you’re finding makeshift ways to lift it off the truck.
 

Brandon-w

Senior Member
Joined
Jan 2, 2019
Posts
3,279
Reaction score
4,983
Location
Yukon
Ram Year
2015 Ram 1500
Engine
6.4
Loves me a dually even more love a12v.
 
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