One of the gravel trucks I learned to drive on was a 1970 Mack R-600. Engine was a 237 Maxidyne with six speed Maxitorque transmission.The differentials were Mack 44,000lb with camel-back suspension(still the toughest in my book),but no power divider.Under 5mph the four sets of wheels were locked up- like a four way lock on newer trucks.It automatically dis-engaged above 5mph.Worked good to-would slog through some really rough going.The lock quit working one day,when backing up or pulling forward in soft ground it sounded like a bad u-joint or spline on a drive shaft.Took it to the Mack dealer and they said the "peanuts" needed replacing.Had that done and was back to the four sets of wheels pulling again.Anyone had experience with this set-up?What made it work?That was the only truck I've seen with this "peanuts" thing.Did'nt have six wheel drive trucks,just used the R-600.Literally wore that truck out-would'nt quit but the frame finally rusted out .They don't build them like that anymore. Thanks for any help, Dominion:drinkup
Look up a sprag unit for a power divider.Basically it is two drums,one inside of the other and the two drums are configured with roller bearings riding in grooves in such a way that if there is a speed differential between the rotating drums the roller bearings interfere between the drums causing them to lock together and to turn the same speed. I imagine the "peanuts" are the roller bearings.There may be other configurations but that is what I think of in my mind when talking about a power divider problem. I don't know about 5mph operation on a Mack,I only know that the power divider lockout switch,if it has it will guarantee that one wheel on each axle will have power with the lockout disengaged,that is,it has no power divider action which guarantees that the axle with the least traction gets a limited percentage of the power making that power available to the wheels with more traction.The weak point on that configuration will be the through shaft,that seems to be what breaks most often.Ron G