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Amphibious 6X6: The Mighty Gama Goat!


Here’s a military vehicle that I bet few of you have ever seen. It’s a 1971 M561 Gama Goat 6X6 and it looks like loads of fun. These things were amphibious and could go just about anywhere, hence the name. This impressive machine is located in Great Falls, Montana and is listed here on eBay with a BIN price of $5,400.


These units were originally developed to operate in Vietnam. There are 6 driving wheels, that is not a trailer. The front and rear wheels are used for turning and they turn in opposite directions. Special training was required in order to operate a Gama Goat.


This is a running unit with the Detroit 3-53 diesel engine which is said to be very noisy requiring PSDs (ear protection for the drivers). This is a 1971 10,000 mile unit. The brakes are in need of repair, the fluids have been changed and 2 batteries are included.


This unit is missing the front marker lights, brake inspection cover, rear tail lights lens and the ALL important hull drain plugs.  At this point if you where to enter the water at a depth greater then the axles it would appear that you would sink.


The owner has 2 units for sale, one is for parts.

M561 Gama Goat farm

The owner also has a M715 Jeep so you could start a military vehicle collection if you wanted.  The red unit, the running one for sale, appears to have been modified with the “roll cage” added.  Maybe without the driving training and taking the curves at the proper speed a roll cage makes sense.  U.S. sales only as per the owner.  Less then 16K were built and you could have one or two today!



  1. Avatar photo randy

    That would be fun to have, but there has to be a better way!

    The price seems very reasonable.

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  2. Avatar photo jim s

    seller has 30 listings including a kaiser M715. this does look like a lot of vehicle for the money if you have a use for it. nice find.

    Like 0
  3. Avatar photo STEEL CRAZY

    W.T.H. Did anybody notice that the odometer has over 10k on it? How could you do that with that lol. My back says No way .

    Like 1
  4. Avatar photo Chas

    Don’t I see four of them in the photo?

    Like 0
  5. Avatar photo Andy b

    I have fond memories of these as a child. My father test drove these for the Air Force. At one point and time he had to drive it on an incline till it flipped.

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  6. Avatar photo Bruce

    I drove one of these back in the early 90’s when I worked for the Idaho Dept of Lands. We had a 300gal tank with a pump on the trailer end. These things go anywhere, but that Detroit Diesel sits right behind you, so ear protection is a must while driving.

    Like 1
  7. Avatar photo Dave Wright

    I bought, sold and owned several of these before the government required them to be destroyed. The best one we had, we put a Chevrolet 350 crate engine in. It solved all the problems with the 3-53 Detroit engine. It was much more powerful and quiet. It was a direct. Bolt into the power cage and the T98 transmission. I sold my last one to a Colorado rancher that was misidentified by the federal agency that sold it as a Dodge 6X6 so it slipped through the sale without having to be scraped. This looks like it was used by another government agency after leaving the Fed as attested to by the red paint. Looks to be a decent price. If I were home……….we would be looking at it.

    Like 1
  8. Avatar photo JW

    Would need a ranch to use one of these, couldn’t imagine driving that thing on the road for any length of time. Pretty cool and if I had a ranch I would be looking at it.

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  9. Avatar photo Howard A Member

    This is really cool, EXCEPT, that God-awful Detroit. Military must have got them for nothing,( or Detroit paid them) as there are much better ways to power this thing. Apparently, it is pretty rare, and a restored one on a military vehicle site is going for $40g’s. Too bad there’s no pic’s of the driveline. While complicated, it seems testers agreed, it would go anywhere.

    Like 1
    • Avatar photo Dave Wright

      These Detroits are aluminum………few engines make over 100HP at the weight of these. Something like 300 lbs as I remember. I have one powering an aluminum workboat we built to be light enough to be launched by a pier crane. When the fed decided these should be destroyed, many engines came available on the surplus market. They are a good engine but noisy……mostly from the supercharger…..and very inexpensive to rebuild. I bought a complete rebuild kit for another one I have last summer for 750.00 including Pistons, liners, mainland rod bearings, a complete gasket set. The engine,transmission and radiator assembly are assembled in a cradle that is very simple to remove……less than an hour in most cases. Standard GM T98 4 speed the same as regular Chevrolt pickups, the goat we built with the small block was heavy in the front end and we decided not to swim it with a load but the additional RPM, power and quietness were wonderful. They are quite easy to drive on the street.

      Like 1
  10. Avatar photo Randy

    As a 33-year veteran of the Army, I can attest there was no love for these things from any of my Soldiers.

    Like 1
  11. Avatar photo sam spade

    I drove a Goat with my ‘ratt’ rig in germany absoutely loved the thing. on of our unit took an autobahn corner too fast and rolled it but I’d still use it to tow my camp trailer.
    Wonderful memories.

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  12. Avatar photo Jay

    I may be a few years too late. I am looking for a couple of M561’s to restore for the new local Museum of the Marine. Let me know if one is still available.

    Like 0
    • Avatar photo Devoy Hill

      I have one for sale, it fires right up as soon as you hit the start button, its in great shape,, it has a red paint job. Give me a call at 985-322-0414 to talk about our gamma goat

      Like 1

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