why is the 5 ton front wheel further up?

just wondering why the 5 tons have the front wheel mounted what appears to be about 10 inches further forward?

Actually the fenders are longer. The front axle is as close to the front on deuces and 5 tons as the late 40's engineering allowed/dictated. The original 5 ton design featured the massive R6602 gasoline engine of 602 cubic inches. They are quite thirsty as far as fuel but they are torque monsters and sound very throaty and cool. They are an excellent engine for the 5 tons if you can afford to feed them. Anyway, the 6602 dwarfs the OA331 that was the original engine for the deuce. The nose of the truck is a little bigger too to allow for a bigger radiator. If you look at the 800 series trucks, their nose is even longer to house the NHC250 Cummins that they have. This naturally aspiriated dieses is 855 cubic inches and moves a 5 ton quite well too.

I also note that the front suspension on these trucks has never been upgraded. I think that although the front axels are very robust, the excess weight of the Cummins engine is causing a lot of stress on the berings and other components in the fron end.
I'm doing a front axel on a M816 now. there is a lot of wear on it not indicated by ether the Od or Tack hrs. I know that shouldn't be trusted but now that it is apart, Ive noted a lot of wear, the axels in the cv joint, bushings, berings spindles and just about everything we have disassembled showa a lot of wear. the truck is a 72 and the rest of it just doesn't seem that beat. Lately I'm reading about 800 fron end problems too. It just adds fuel to my theory.

I *think* those axles are rated at like 11,000lbs so there a chance it may just be neglect from lack of maintenance.

Remember, the 816 is one of the heaviest of the 800 series, at some 33 to 36 K. You have to make sure you keep plenty of grease on the front end, and watch tire pressures very carefully. Ask Ron (73M819) what happens when you fly your 800 series truck.

So, upshot is that the old design of these trucks, featuring the R6602, dictated an axle positioning that stuck around even when newer power plants were employed?

Trango said:

So, upshot is that the old design of these trucks, featuring the R6602, dictated an axle positioning that stuck around even when newer power plants were employed?

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Some pics of early 5 ton engine bays here. Continental, Mack, and MultiFuel.

The five ton axle is larger to start with. This necessitates moving it forward out of the way of the oil pan. Add the fact that they added a hydraulic power steering and the neccessary pump on the engine which also adds to the clearance required in the front of the engine. This is proven when you try to install a 5 ton power steering system on a deuce and find out that the pump is almost in contact with the radiator and its supports.

Besides....a 5 ton is bigger...RIGHT???????????????????????

18,000...awesome!

From what I recall they also use the five ton sheet metal on the ten tons but the axle is centered on them.

spicergear said:

18,000...awesome!

From what I recall they also use the five ton sheet metal on the ten tons but the axle is centered on them.

Click to expand...

Cab and hood sheet metal is the only thing on a 10-Ton interchangeable with the M39 series 5-Ton. Axles, frame...pretty much everything is completely different.

these trucks need to climb a 60% slope, I believe that is the only reason the axle is where it is, with out the bumper digging in , otherwise the steering radius would be preferred a little bit back,Also when adding a winch to these trucks the bumper would always hit the ground first up a hill, all else could be adjusted . Ford pick ups used to say in print the axle are forward is so they can approach a steep incline, and it works, same for our trucks, engine longer winch makes em even longer ............. axle up front to climb.