XM-778 2 1/2 ton Cargo Truck, W/W

[sigo]

Fred Crimson's U.S. Military Wheeled Vehicles has one paragraph on page 347 about the XM778. It was built by White as a potential replacement for the "Reo" (M44) 2.5 ton trucks and tested at Yuma Proving Grounds in 1967 as part of a "Quality Assurance Test". The truck is described as having a strong resemblance to the M35 except for super single tires, outboard brakes, and louvers in the side of the tilting hood. The photo in U.S. Military Wheeled Vehicles looks very much like a M35, but it clearly has a tilting hood. You can't see the axles and there isn't much more in the description to identify features of the XM778. I have to wonder if there are more than one version of the XM778 or if your hood/front clip was modified since yours does not seem to have a tilting hood.

Based on the descriptions of other trucks that were looked at over the years to replace the M44 series I'll offer good news and bad news. The good news is you seem to have a very unique truck. I see no evidence to say for certain it's the only one, but I'd wager there aren't more than a couple out there. The bad news is I'd also wager a manual does not exist, or at the very least will be extremely difficult to locate.

 

[AndrewH]

I have read the same book and I agree. I kinda suspect if this particular truck ever did have the tilting hood it was probably damaged during forest service duties and with the original type sheet metal not available, the M35 style steel was used to repair. I haven't yet found evidence of hinges or latches for a forward tilting hood so I don't know if this truck was ever so equipped.

 

[MatthewH]

If I remember in Freds book, they showed a version with a 109 style box as well

 

[AndrewH]

Time for David Doyle.

Wish my crystal ball had not been turned in. Sure would like to see what those numbers brought up.

You have me intrigued and that's been a fairly rare occurrence on here lately.

I'll try to get ahold of David. Thanks! If you happen to stumble across access to the crystal ball again let me know please!

 

[sigo]

If I remember in Freds book, they showed a version with a 109 style box as well

Great memory. Page 345. It does look like a variation, but it's listed as a XM782 as tested at Aberdeen Proving Grounds. Technical details are unavailable, but it could be just an M109 with outboard brakes and super singles. The front clip is not the same as the XM778.

 

[AndrewH]

If I remember in Freds book, they showed a version with a 109 style box as well

Yes, XM782

 

[HanksDeuce]

I had to research wet braking systems to figure out how they work. It may be something like the video below, eh?

http://youtu.be/dvCYBUOtKrk

 

[AndrewH]

I'm not exactly sure what all is going on inside that hub yet as far as the brakes are concerned but I know they are air actuated. I am digging for information on the as brake maintenance is kinda a big deal. The air line appears to go into the axle housing, so there is some magic going on somewhere to get it into the hub. These brakes do not offer a mechanical parking brake. The truck still uses the M35 style hand brake.

 

[AndrewH]

Time for David Doyle.

Wish my crystal ball had not been turned in. Sure would like to see what those numbers brought up.

You have me intrigued and that's been a fairly rare occurrence on here lately.

Davids inbox is full. (ddoyle) If anyone has his info could they please contact him? Thanks.

 

[Jeepsinker]

One of our members had one of these for sale in the classifieds a while back... maybe a year ago or more. I wanted it but couldn't afford it at the time, and the tires were dry rotted, so towing it home with a bar was a no go. If memory serves he was only asking $3000, maybe less. Also, good luck finding some of the parts that you will surely need at the wheel ends anyway. Really cool in the meantime.

 

[rustystud]

I had to research wet braking systems to figure out how they work. It may be something like the video below, eh?

http://youtu.be/dvCYBUOtKrk

My old dozer uses that system for braking, but I never saw this system used on a over the road vehicle.

 

[brianp454]

Nice thread!

 

[citizensoldier]

Yes this is the vehicle that was for sale a few years back and I am very happy to say it found its rightful home with Andrew. He has the knowledge and mechanical skills to keep this rare bird going for sure. Does anyone have Doyle's regular email? I lost it in a computer crash some time ago. I feel he is our only hope at maybe digging up some proving ground testing info or program files on this beast. Its a interesting bit of history for sure.
On another note it would help him to find a old Reo or Curtis Wright gasser with descent sheet metal for parts if anyone knows where one might be hiding.

 

[citizensoldier]

Hey Andrew. I never got around to poking at it but is that a 427 engine? Always wondered about that being a non turbo and early prototype.

 

[cranetruck]

Doesn't Cranetruck's XM757 have an outboard brake setup? Those new shoes Ferro found for him look very close to the same size as well, I think they were 16-20's

No, the 5-ton xm757 is a very different creature...


The tires look the same, but the xm757 ones are low profile and should really be marked 16/70-20 for a 70% aspect ratio.
The brakes on the 757 are 100% air, I'll get a few pictures in a minute...

 

[cranetruck]

Here is an inside view of the drum brake (they can be serviced with the wheel in place, btw).

 

[Jeepsinker]

I thought it might have been the same one. Something about the Circus paint scheme was familiar... And there a new nickname is born. It shall henceforth be known as "The Circus Wagon ".

 

[AndrewH]

I thought it might have been the same one. Something about the Circus paint scheme was familiar... And there a new nickname is born. It shall henceforth be known as "The Circus Wagon ".

Veto! Unless I find a specific reason not to, I'm painting it white.

 

[AndrewH]

Hey Andrew. I never got around to poking at it but is that a 427 engine? Always wondered about that being a non turbo and early prototype.

Nope, sorry Lane, its an LD 465-1

 

[citizensoldier]

Nope, sorry Lane, its an LD 465-1
View attachment 588105

No need to be sorry...lol.. I just recall allot of the early trucks from when they switched from gassers to diesel were the 427 and never looked at the tag. The inside of cranetrucks drums are interesting. I wonder whats inside yours?