2003 Sterling/Freightliner SC8000 Cargo- Cummins, allison & custom marmon-herrington 4x4: perfect blank canvas for heavy overlander


New member
2003 STERLING/FREIGHTLINER SC8000 CARGO CABOVER FLATBED TRUCK Custom and rare Marmon-Herrington 4x4 system! Cummins ISB 5.9 liter 24 Valve with tasteful reliability upgrades! Bulletproof Allison 5-speed automatic transmission! Drives, rides, and brakes extremely well. Plenty of power. Only 16k original miles!

PXL_20240101_173938701 (1).jpg

Intent was to convert this truck into an overland expedition camper, but plans have changed due to an overseas move. I don’t want it to sit for years in a pole barn, so would like to find an owner who can use this truck-- preferrably would like to see someone build an overlander, but happy as long as it is being used!

You will not find one with mileage close to this for less than $46,000. Most of these on the market have well over 200,000 miles. Even fewer have the custom 4x4 system and a flatbed.

The engine is the Cummins ISB 5.9L 24V 225hp turbo diesel with the VP44 fuel pump. The engine oil and filter were last changed at 15,700 miles with Valvoline Premium Blue 8600 15W40 and a Fleetguard filter.

The transmission is the reliable Allison MD-3060P. It's known as tough tow/haul trans. Sale will include a filter and three gallons of correct transmission fluid for a service. Currently electronically limited to 5 gears, this transmission has the covetted sixth gear that can be electronically enabled to provide even better high speed cruising and MPG on the highway. The differential gear ratios are 5.65. The tires are 11R22.5 and there are mostly Michelin X. The outer tire on the right rear is a Firestone. All tires have decent tread, but are showing some slight cracking from age.

The rare, but U.S. military-proven, Marmon-Herrington All-Wheel Drive system has the MVG 750/R Series transfer case and functions exactly as it should. For off-highway applications (or snow/ice) the Marmon-Herrington 4x4 system has an optional driver-controlled toggle for the air shift system for the high-low transfer case and an optional driver-controlled toggle for an air activated front differential lock. Front and rear differentials are both Meritor.

The flatbed is a 9’ wide x 14’ long Knapheid cargo flatbed with stake body pockets – truck does not have the stake body sides although they can be found online for reasonable cost. It has a headache rack, however that will need some welding to be perfect, but that shouldn't matter to someone looking to fit it with a habitation box. The rear of the flatbed has a Waltco 2500-pound capacity electric cargo lift which works very well and has a wide folding platform for lifting pallets and other large items. There is no tow hitch, but one could easily be fitted once the cargo lift is removed and sold.

Many of the lights were replaced with LEDs, including the headlights. The headlights are very high-end Trucklite/Rigid brand 7” round headlights that were over $500. They are much brighter and have a great beam pattern compared to the old halogens. All parking lights and signal lights function perfectly, aside from the right turn signal light on the dash which does not illuminate, but the signals and 4-way flashers work. The truck is fitted with an A/C system which works very well. The blower is strong. The heater works well, but the control cables (one that opens the heater core valve and one that closes the vent) both are frozen and likely need replacement to regain HVAC control in the cab.

Upgrades: New engine control management box with stock/original programing done in 2021. At 15,850 miles, fuel system was upgraded with a brand new AirDog II-4G 100 GPH Air/Fuel Separation Lift Pump ($850) which fixes known issues with fueling the VP44 injection pump in the 24V Cummins. This pump was installed with an AirDog Sandwich Mounting Frame Bracket Kit ($130). Six new DDP 75hp Injectors ($800) were installed. A Glowshift fuel pressure gauge ($100) was installed in the dash along with the sensor and sensor wiring, but power is not wired to the gauge. The old 100 gallon steel fuel tank was removed and a brand-new polished aluminum 50-gallon fuel tank was installed on right side with new fuel level sender, new stainless steel fuel tank straps, and new rubber protective padding. All new PTFE stainless steel braded fuel lines and aluminum anodized AN fittings (8AN for fuel supply and 6AN for fuel return) were used for fuel plumbing. Truck comes with everything needed to add a second 50-gallon aluminum tank to the left side (stainless braided PTFE lined fuel line, AN fittings, tank, brackets, straps, strap rubber. I had intended to do this when I was building the overland camper to add capacity for long hauls and to balance the weight from side to side.

The truck has three commercial grade batteries that hold a decent charge, although they are getting a bit older. I notice a slow start if the truck sits for longer than a month. Needs a replacement plastic battery box cover. They are available online.

This truck has air brakes and the air brake system passes all functions and leak down checks. Brakes feel very solid and strong. The truck also has twin air horns on the roof.

The interior is decent. The seats are excellent. The floor looks good except for a small area on the drivers side that was treated with Eastwood Rust encaspulator. The dash has one vertical light panel/cluster that is only attached to the dash panel on the right side of the steering wheel with some tape. Some plastic bosses that hold screws cracked, allowing the small vertical warning light panel to drop. This is a quick epoxy fix, but the below freezing temps are preventing me from fixing it right now. The headliner is sagging, but it is very high above your head and not a major nussance. This could be easily replaced or refastenned. The most rust on this truck is in the driver’s side door jamb near the edge of the floor. Eastwood rust encaspulator was used on it to prevent spread and it is still structurally sound. It would be a relatively easy sheet metal welding repair in the future and is prudent. There is a dent where the passenger mirror mounts on the outside of the passenger door. The passenger door lock latch on the inside is missing. This is easy to replace. The door interior grab handles are missing, but could be replaced with some fitting with some custom braided paracord door pulls. All glass and mirrors are perfect, aside from some hazing on the right/passenger vertical plexiglass panel forward of the door. The white body paint is in good shape aside from some aging. The parts that I have polished really come back to life.

The 5.9L Cummins turbo diesel starts up, idles great, and runs great.

The vehicle stands very tall and looks aggressive. It is best described as a civilian version of a military LMTV, with better highway manners and gas mileage. The frame does not have a single bit of rust on it, not even surface rust. The engine and chassis do not show any rust. Most of the rust on this truck is located on the flatbed subframe, although there are no spots of structural concern and most is surface rust.

Maintenance: From 10 to 15k miles, this was a government owned & maintained vehicle. At 15,750 miles, the cooling system was completely flushed with distilled water and then filled with 50/50 distilled water and Extended Life Coolant and the cooling system filter was changed with a Baldwin filter. The suspension, steering, U-joints, brakes, etc. were/are regularly serviced with heavy duty grease.

The air brake system passes all leak down checks. Tanks are drained and drain plugs are always removed when parking for the night.

There are endless possibilities for this truck and most of its service life remains. Use it for construction, heavy cargo movement, landscaping, put a box on it, etc. But I sure would love to see someone build an offroad expedition camper/overlander.

Truck is located in Woodville, VA (very close to Sperryville and Washington, VA.)

Asking price is 21,500.

Feel free to ask additional questions or schedule a time to see and drive it. Thanks.

The Sterling SC8000 is quite rare, however, for research purposes, these same trucks are also badged as Freightliner FC70 and FC80, Sterling SC7000, Ford CF7000 and CF8000. It is also extensively used by the Indian Army as a cargo vehicle badged as the Ashock Leyland Stallion.

Last edited:


Expedition Leader
Nice truck. If that has a front diff lock that is a very rare bird, usually they only put the diff locks on the rear.
  • Like
Reactions: mog
I found the identical twin of this vehicle for sale in PA, right down to the orange flatbed. Half the miles but double the price! Were you going to leave the wheels as is or convert to Super Singles? How tricky is it to unlock that 6th speed?

Sid Post

  • Super Single conversion
  • Transmission unlock
  • Electronic fuel injection and related hardware?
Good question on the Super Singles on the rear! Does the axle need to be swapped to keep the front and rear track the same?

How does unlocking 6th speed in the transmission affect road speed and MPG?

Which variant of the Cummins engine does this use? Does it use the same one in Dodge pickups that physically breaks the pump when when the fuel pump dies? Specifically, is it the electronic Bosch fuel injection pump or, is it the older school mechanical pump that doesn't have this fatal flaw?


New member
I made the trip down to Virginia to check out this truck. If you're serious about a rig like this, I highly recommend you check it out for yourself. The photos don't do it justice. It's in great shape and ytsurrr knows his stuff - he's made some very tasteful and practical modifications to it. Highly recommend. The one and only reason I didn't buy it is because I realized I'll be doing more highway driving that offroading. I hate being practical. I still want this truck.
Anyways... I can absolutely vouch for both truck and owner. Hop on it before someone else does. And at this price it's a steal. Feel free to contact me if you want to hear my thoughts/see the pictures I took as an unassociated third party.


New member
Thanks for all of the questions and thanks to caboverlover for the support. Was a great day with the truck.

This truck does have the front locking diff, air locker with switch and indicator light on the dash. Really neat to hear it engage. During the test with caboverlover, we slipped a bit in some soft mud and poorly packed driveway with the front right tire (had the air up to 90-95psi in the Michelin X road tire, so very little traction). We were quite close to a tree too. We put it in neutral, flipped the transfer case to low and engaged the front axle, then slowly pulled right out of the situation with full control.

It does not currently have a hitch due to the 2500# capacity carho lift on the back which is driven by a large single hydraulic cylinder in the middle. I am sure there are some sort of swing out hitch options, in fact I think I looked before. Best option would be to pull the cargo lift, sell it, and use some of the cash to put a real hitch plate between the frame rails.

As far as super singles, another owner of one of these (rare to find them) put 445/65r22.5 tires on his. They fit great and look amazing. I attached a photo. No axle work and it tracks direct. He also unlocked his 6th gear and says his rig cruises nicely. He actually has plans to add a habitation box. He doesn't have exact MPG numbers before and after the 6th gear unlock, but it's obviously better with 6 gears. In current form limited to fifth gear, the truck is turning around 2200rpm near 55 and 60mph, so the 6th gear would help, particularly on flatter highways.

Truck currently has the 5.9 24 valve Cummins ISB which does have the VP44 fuel pump, which is the one that has major problems with heat if the lift pump supply is not exact/maintained. This is why the Air Dog fuel pump is the best upgrade to make this fuel pump live. And the fuel pressure gauge is an important addition for the same. Still, many people do make the conversion to the older mechanical P-Pump. As it sits, fueling is plenty reliable.

Also forgot to update my asking price. Due to pending overseas move, I'm asking 24,500. I just don't want to store it for 3-5 years without it running. Someone else should use it!

Thanks for the questions and I hope this post helps answer them. Keep them coming. I enjoy sharing this incredible truck.


  • received_2183431048685508.jpeg
    2.5 MB · Views: 147


Expedition Leader
Does it have a rear diff lock too?
The VP44 is a good pump. Just put a good lift pump on it with a fuel pressure monitoring device and you're good to go, you've already done that. The 24 valve with a VP44 is actually my favorite Cummins, easy to work on, good driveability, and they sound good too.

This is a heck of a deal for a rare nicely optioned rig.


New member
Does it have a rear diff lock too?
The VP44 is a good pump. Just put a good lift pump on it with a fuel pressure monitoring device and you're good to go, you've already done that. The 24 valve with a VP44 is actually my favorite Cummins, easy to work on, good driveability, and they sound good too.

This is a heck of a deal for a rare nicely optioned rig.
Does not have the rear diff lock. Fuel pressure gauge has the sensor plumbed in between the lift pump and injector pump and is installed in the dash, but to be extra clear, it still needs power jumped off of wiring in the dash. That should be simple for the new owner as the dash is quite utilitarian and affords good access behind the gauge panels. Thanks for the post!
Yes! That SS is more in line with what I was picturing- it just looks right. I've been baffled at the lack of overlanders based off of these Cummins 5.9 trucks and all of the differently branded variants, but it's probably down to how rare the 4x4 equipped trucks are. I'd take this over an LMTV any day. Seems much more civil (and simple). GLWTS


New member
Update! I had to move the truck today to make room for a shipping container delivery. Got to test it's mettle in the snow and that 4x4 (transfer case low, front locked) is truly amazing. The engine shows it's stuff too in those low gears. At idle it "crawls" nicely up hills. I didn't even use a bit of throttle to move it around on some hills in the snow. Also captured some neat photos and figured out what was wrong with the heat. One of the control cables is stuck, preventing the heater core valve from opening. I unhooked the cable, opened the valve and the heat was kicking. Truck started extremely well below 20 degrees F this morning. I shot some wd40 into the control cable and next time out, I'll see if it frees up.


  • PXL_20240118_193224873.jpg
    4 MB · Views: 89
  • PXL_20240118_193452787.jpg
    4.6 MB · Views: 93
  • PXL_20240118_193500615.jpg
    4.7 MB · Views: 87
  • PXL_20240118_193514001.jpg
    3.9 MB · Views: 86
Last edited:


New member
Had a question from a member about interior photos, particularly about the size of the seating area, and I figured I'd share the best photo I took recently. I'll take some more this weekend and get them posted. Thanks.


New member
Had a very helpful and gracious Allison tech reach out and let me know that this truck has a 3000 series Allison transmission, not 2000 as I had it orignally listed. He said I might be able to enable 6th gear simply using the mode button on the transmission shifter. I did look at the driver's manual that came with it and snapped some photos of the Allison transmission section which indicates the operation. Included a photo of all the manuals the truck has. I also snapped a photo of the build sheet in the warranty booklet which gives more detail that I failed to include in the original posting. I am excited to try the mode button on the Allison MD-3060P. Also learned its a 225hp model Cummins ISB and the axle ratios are 5.57 and both are Meritor.



  • PXL_20240124_110030821~2.jpg
    875.3 KB · Views: 34
  • PXL_20240124_110052748~2.jpg
    1 MB · Views: 33
  • PXL_20240124_105818152~2.jpg
    2.3 MB · Views: 32
  • PXL_20240124_110155090~2.jpg
    1.8 MB · Views: 38

Forum statistics

Latest member