Differential and sprag or other system

[Robo McDuff]

OK. Somebody explain me this.

1973 5-ton M51 A2 Multifuel

Front wheels jacked up and free, rear wheels on the ground.

Both front wheels free, when turning one it will turn the other in opposit direction.

In neutral AND in forward gear, keeping one front wheel fixed (not turning) and the other free. If I turn that free wheel forward, it moves the cardan shaft (between front differential and tranny). If I try move it backwards, no movement.

Gear in backward, I can move the free wheel backward but not forward.

I thought that on a permament 6x6, when gearbok and tranny are engaged, its impossible to turn the cardan shaft?

Is this the effect of a sprag? I thought later models did not have that?

 

[gringeltaube]

........................................

I thought that on a permament 6x6, when gearbok and tranny are engaged, its impossible to turn the cardan shaft?
.........

Your's is NOT "permanent" or full-time 6WD.

Is this the effect of a sprag? I thought later models did not have that?

YES. Front axle is driven "on demand" only. All early 5tons including 800series came that way, same as Deuces with sprag T-cases.

G.

 

[Robo McDuff]

Thanks, so that behavior was normal?

When does the thing jumps in? I can't reach my manuals today to check myself, I am using internet away from home.

 

[KsM715]

When your rear wheels start to spin the sprauge will catch and spin the fronts.

 

[Robo McDuff]

Thanks. Not that I planned to do it, but putting front-wheel locking hubs on your 5-ton for highway work is nonsense in that case.

So basically I have a 4x6 on highway and 6x6 in the mud. Great. Learned several new things today, both from praxis and from this forum.

 

[gringeltaube]

thanks, so that behavior was normal?
..................................

yes.