I really need to buy this military tug, and honestly, so do you. Do I live in a one-bedroom apartment with limited parking? Sure. Is this tug even street legal? No. Do I own an airplane that needs to be moved around? No. Is the $4,850 asking price a little dear for a cheap bastard like me? Sure. But none of this matters, because I can easily, easily rationalize this purchase. You see, what you’re looking at is an amazing starting point for a budget, Moab-crushing, rock-crawling beast. Hear me out!
I’ve been drooling all over my keyboard these pasts few weeks staring at this 1975 Coleman “G-40” military tug for sale in Las Vegas:
Obviously, I like it because it’s incredibly cute, with its tall roof but ridiculously short wheelbase, and its hilariously skinny hood. Everything is so squared off, and the tires are just so gigantic; it all looks so stubby and awkward, and I just can’t get enough! But this tug has a lot more to offer than just great looks.
Under the hood is a Chrysler 318 cubic-inch V8 motor sending gobs of torque to all four wheels, which are all steered hydraulically! That’s right, this little tug is essentially a V8, four-wheel drive pickup with four-wheel steering!
Since I’m sure you’re wondering how that looks when it’s functioning, the answer is: Amazing. In fact, you can watch the glorious four-wheel steering in the video below uploaded by Low Buck Garage. This YouTube channel is run by a guy named James, whom I interviewed and wrote an article about last year. James is my Jeep hero, so I find it hilarious that he already owns this really irrational machine that I recently found myself lusting over:
At the end of the video above, James asks the question I asked myself upon finding the Facebook Marketplace listing: What do I do with it? The answer is actually quite simple: Turn it into an off-road rig. The thing already comes with 40+-inch tires, it has short overhangs, a small wheelbase, four-wheel drive, and absurd gearing. It’s a fantastic starting point for a rock-crawler.
I just found the official technical manual for this tug, and my god is it a deep rabbit hole.
Look at this lovely diagram!:
The basic setup is this: There’s an “industrial type” Chrysler V8 motor hooked to an Allison four-speed automatic transmission, a transfer case (which provides a 2.6:1 gear reduction and splits power off to the front and rear axles — it includes a differential that can be locked), and leaf-sprung solid axles with between a 6.2:1 and 7.2:1 gear reduction (depending on the exact Coleman G-40 model).
Let’s pause there for a second. A 7.2:1 axle ratio, a 2.6:1 low range reduction, and a transmission with a 3.45:1 first gear ratio — that all multiplies out to a 65:1 crawl ratio. That 140 horsepower V8’s motor makes 220 lb-ft of torque, which gets multiplied by 65 by the time it gets to those 11.00-20 tires (those are 43 inches). A modern Jeep Wrangler Rubicon has a numerically larger crawl ratio at over 90:1, but still, 65:1 is decent; this airport tug should have plenty of tugging “power,” and that means it’d make for an excellent low-speed rock crawler.
Obviously, at 11,000 pounds, it’s a bit large to be amazing off-road, but 12 inches of ground clearance at each axle is solid. The eight-foot overall height, huge bumper up front, and low-mounted draw bar out back are a little concerning for off-roading, but some plasma cutters could take care of those to reduce the risk of rollover and improve the approach and departure angles a bit.
More importantly, we need to talk about the steering system, because it’s cooler than you think. First off, the G40 has a better steering radius than pretty much any car on the market, including the no-longer-on-the-market BMW i3, which has hilariously skinny tires and turns on an absolute dime. The i3’s turning radius is 16.2 feet; the G40 tug’s turning radius? 15 feet! Even more incredible is the fact that the front and rear axles turn independently. Seriously, read this:
Here, let’s watch another video of this amazing steering system in action:
Here’s a diagram of the hydraulic steering system showing the hydraulic steering cylinders for each axle:
For you nerds out there, here’s the G40’s full “table of specifications”:
Top speed, as you can see, is just 24 mph in fourth gear, but for an off-road rock-crawler, that’s all one needs.
The more I read the G40’s technical manual, the more I’m convinced that this tug might be the ultimate starting point for a cheap off-road buggy build. Seriously, check out this little bit of info about the axle shafts: “These axles have one-piece forged axle shafts that can be readily removed without lifting (jacking) the tractor.”
Forged shafts! And easily replaceable!
Obviously, the heft and size are an issue, and parts availability can be tough, but with some weight reduction methods, this $4,850 tug could be a great way to build an off-road buggy without spending a fortune. Seriously, a set of Dynatrac axles for a Jeep can cost well over $10,000; a lift kit other provisions needed to fit 40-inch tires on a Jeep Wrangler also costs lots of money.
But the Coleman G40 is ready out-of-the-box: It’s built to handle 43-inch tires, it’s got decent gearing for crawling, it’s got an absurdly tight steering radius to help you navigate tight trails, its overhangs are short enough right out of the box (and can be reduced; looks like that bumper will come right off), and most importantly: it’s cheap.
[Edit: As some have pointed out, I’ll want to throw some new, taller springs on it to give it some wheel travel. This will likely require some modifications to that amazing steering system. -DT]
And you know I love cheap.
My former boss & I stopped to look at one of these for sale a decade or more back. He was looking for something to plow snow at our shop. It was around $3k, iirc. Very cool, but we quickly decided parts would be an issue.
ended up with a tractor made out of a 1937 Plymouth and old Ford tractor parts-that was an adventure!
I suspect you will encounter some kind of centre of gravity problem, taking it out rack crawling, since it is rather tall and narrow, which is not any concern at all at flat air fields.
But that’s exactly why we love your stuff, because you come up with these ridiculous impossible seeming ideas. You sure are one wild and crazy guy!
(well, THAT pop culture reference is probably also lost on you 😉 )
Yeah. As I was reading I pictured David tumbling backwards down a steep incline. I hope he added a four point harness.
Finally! Something I could use to tow aircraft through riverbeds. Too bad it’s not a 7 seater, that would be purrrfect.
Please somebody just buy this for David “Rusty” Tracy!!!
You imagine getting that severely mud stuck!!!
It is now a feature of the trail system, “Tracy’s Folly” a landmark for generations to ponder.
Not to mention that steering if it could actually travel at speed.
David, you’ve had some great ideas and I’m hoping you have many more, this is not one of them.
This company has a fascinating history. Including building race cars that ran at Pikes Peak and Indy.
https://www.museum.littletonco.gov/Research/Littleton-History/Other-Topics/Harleigh-Holmes-Coleman-Motors
That Coleman Indycar is sweet looking.
That’s the issue with most tugs, they’re built intentionally with no or almost no suspension and they’re built to be super heavy so they’ll have enough traction to tow a plane. Turning them into off roaders is highly impractical and very expensive.
You are not the first nor will you be the the last to have this idea.
I always thought these would be great off road. Until I drove one off road when I was stationed in Florida and it sunk to the frame. Also, no suspension is wild!
I’ll clarify, the later model Coleman’s we had when I was a flightline maintainer were solidly mounted with no suspension. The tires were the suspension and you could get some great bounce in them
Okay, so how do you get it to your favorite off roading place? I mean, you’d have to tow it there with like an F-350. It would be amazing, but comically impractical.
You say 8 cyl. The guy in the video says 6 cyl. You say 24 mph. Top speed but the video says 40 mph. But take it to the local truck pull and enjoy dragging any truck around. Put the back bumper on another 1,000 pound of solid steel and enter a demolition derby. Just let them ram into you as you do deep turns and let the bumpers destroy them. A rock crawler does seem an ideal solution but gotta loose serious weight and tow it. Or wait for winter and tow cars out of being stuck. Or go to the local mud pit and tow people out. Put a plow on it and plow pretty much anything.
The 1975s were V8s, but some others were I6 flatheads.
When you’re ready to knock over a bank. Literally.
They could have used it in that Fast + Furious movie where they stole the bank vault.
The G-40 would be a lot slower than the Chargers but a lot more believable. 🙂
This thing gives off strong Killdozer 2 vibes…
“Oh Lord, won’t you buy me a Coleman “G-40” military tug”
I am confused as to why you think this is a good base for an offroad vehicle…
It’s mostly obscure drivetrain parts. It looks like the axles have a terrible steer angle. It has an uncommon hub/wheel interface that is going to limit your tire selection.
The weight is ridiculous.
You have a decent but not amazing low gearing but no options for higher gearing so good luck if you ever need wheel speed.
It’s stupid tall.
What sort of joint type and strength does it have joint-wise for steering in those axles? And whats the actual size of the axle shafts? Or the spline count?
If you could afford the petrol this would probably crawl straight up Pikes Peak without the road, or MOAB stuff with little to no effort. As such the opportunity for fun and mayhem are increased by a mean factor of 10.5 vs the mean Jeep ownership fun factor…just science. Sometimes fun shit outweighs sensible thinking.
I address most of these in the blog, and still think it’d make for a great rock-crawler.
Sure it is really tall but i wonder where the center of gravity is. It doesnt seem to have a lot of weight high up. So no flip over worries.
Yeah, with both inches of wheel travel it probably has…
No suspension travel, David. I know you’re an automotive engineer and are capable, but retrofitting a suspension on this beast would be a deep project.
You’d have to modify a few things, no doubt
This reminds me… do folks build hydraulic-drive crawlers? Stick a standard wheel motor at each corner, make it 4-wheel steering for yucks, use any suspension setup you like. You could probably rob a couple zero-turn mowers for parts to make a smaller one. Seems like cheating honestly.
That’s an idea I’ve had. But with hydraulic fully articulated suspension that’s all controlled by a computer with 3D cameras.
James @ Low Buck Garage did a series on his on his youtube channel. It is fascinating and useful in his back yard, he manages to haul his behemoths around using that. Definitely something to get if you have a property to go with it.
Like it or not US military industrial complex is a trickle down economy especially for engineering types on a budget, you can get retired machinery of good quality like this (and huge mills / lathes) for pennies on a dollar.
Do people not read the content?
“In fact, you can watch the glorious four-wheel steering in the video below uploaded by Low Buck Garage. This YouTube channel is run by a guy named James, whom I interviewed and wrote an article about last year. James is my Jeep hero, so I find it hilarious that he already owns this really irrational machine that I recently found myself lusting over“
Wow. That’s a lot of mass!
Even if you’re able to shave off 1,000 pounds, you’re still weighing roughly 2.5 Jeep Wrangler Rubicons (JWR).
Add in the dozens of GALLONS of fuel needed for a full day of off-roading and you will put new meaning to ROCK CRUSHING????
DT. You need this! Jesus if a vehicle ever screamed out buy me this is it. And you could sell some of your shit to pay for the transport down to LA. I can see it now, This mean machine, DT, and (insert hot chick image here), just chillin at Huntington Beach at sunset. Can you imagine the shit you and Chainsaw Boy could do/pull with this? Crap, Google says it’s a long ass way to Denver, so I suggest you just BUY IT NOW! Thank you very fine.
Right? Look at the approach angle! Look at that departure angle!
I’m trying hard to think of a way to install a dual range or secondary gearbox like some trucks or military vehicles use. Some modifications to the transfer case may also be necessary, but I’m not totally certain. The goal would be to have the ability for use on-road because why not while still being a badass offroader too.
Do your crawling in REVERSE at 94:1!!
Genius!
Lose that 1,000 lb bumper and you might be able to do 28mph. That’s a good cruising speed to drive it to Moab. I’m sure Torch will be happy to drive a chase car.
Otto’s gonna ‘Nope’ outta that one!
Is that better or worse than Project POStal? 🙂
Since this is from 1975 and the manual calls for regular (leaded) fuel, and because it’s a 318, you can swap the heads for a set from a 360 truck engine: the truck heads have hardened valve seats and offer better flow than the stock 318 heads.
As with most tug vehicles, I’m having trouble figuring out where the 11,000 pounds are hiding. Is the front bumper a solid chunk of steel? (It wouldn’t be too surprising to have a significant counterweight on the front of a tow vehicle.)
I think the whole tractor serves as its own counterweight. I’d love to see how it handles snow with that much weight over 4 relatively narrow tires. I’ll bet it cuts right through the snow and drives basically like it would on a wet road.
Yes in the video said 1,000 pound solid chunk of steel bumper. Also said the missing rear bumper is the same. So 9,000 pounds without bumpers.
The issue I can see is that unless you live next door to your off-road park, you either need to drive it there (at a top speed of 24 mph) or trailer it (which probably requires an HD truck).
That was my first thought. He’s going to need a heavy equipment trailer and at least a 1 ton dually to safely tow something that heavy and tall.
Assuming 15,000 lb including the trailer, plenty of SRW trucks will handle it, hell my 1 ton gasser would manage. But you aren’t safely moving it with a half ton or a J10
I am pretty sure James stated 40 mph top speed and 6 cylinder chrysler motor.
I mean DT attached the spec sheet showing 8 cylinders and 24 mph…
That is an incredible looking “little” truck. My first “car” was a 1974 Land Rover 88. This Coleman rig would absolutely annihilate the Land Rover off road. $5,000 is nothing for all of its capabilities. The Achilles heel is trying to trailer around your 11,000 pound side-by-side.
but the 88 would get up to 50mph unless you had the overdrive
We had the Fairey overdrive and 7.50×16 tires, so we could could cruise pretty comfortably at 60-65 mph. That was a great little truck.
Nice find!
That narrow hood throws off my perspective. The manual page indicates a 78.5-79.5″ overall width, but it looks much wider to me (knowing that the hood is wide enough for a 318).
As my Alaskan eye doctor would say, it’s an optical Aleutian.
I’m stealing that joke…
College of the Ozarks in branson used to use one of these as a snow plow, I never knew it was so interesting.