Heavy Haul Differential Brand of Choice

If the front axle did allow "inter axle differential" action, wouldn't the front axle always be the one to spin out as the typical "power divider" splits the power in half? So 1/2 the power would be going to the front axle, and the other 1/2 would be going to the rear two axles.

 

Pretty much. If any of the 6 wheel ends on a tridrive spin out, you're stuck. I've yet to see a tridrive without 6 way lockers. Usually both power dividers are on 1 switch and the axles have individual locks. Pretty much have to kick in the power divider lock once you leave the pavement.

 

So no such thing as a front 3rd member without a power divider? I.E. full power to both axles all the time? Thought I had seen mention of such a beast in some Eaton literature last time we blew the power divider out of our 46K rears.

Seems to me like whenever the going gets tough and something fails, it's the power divider...

 

Actually every diff should be powered regardless. Tandem or tridrive. That's why tridrives are pretty much useless without 6 way lockers. Drive through a hole and any one set of duals comes off the ground you're screwed. Pretty sure I remember my dad saying he'd lock in the power divider the moment he pulled off the pavement just to prevent that from happening.

 

If you can get them still, you could try Eaton 2 speed 46,000 rears with Detroit lockers on all 3 drive axles . I had a 1996 Western Star new from the factory in Kelowna built like that, except just a tandem. Double lockers. Never spun out or tore up a diff in the 15 years I ran the truck. Did a R and R, inspection, and new bearings as preventive maintenance after about 9 years of service. Ratios of 3.90 for highway and 5.32 for bush and mine roads, and steep, short pulls like the hill up from the scale at Pac. Highway at heavy weights. Great truck, actually..