Dual range bogie drives

.Yeah .......I think doing the range change to low before you stop is the way to go.............
..(if you want to take off in low that is.)...........
A change while stationary may lead to a (say) butt gear condition where the air might
be primed to go but the gears ( or what ever ) are unable to slide...........
Then as you attempt to move off, the gear engagement may go off with a bang...........
But.......if one diff did not change, for what ever reason ... one in high and one in low
should move off ok.....the power divider would take care of that...............
EXCEPT... ...if the diff lock (inter axle lock) is still engaged, ..........
that is when the shite hits the fan............
Another relatively little known KW quirk was.......... if you are in ,say, high range and engage
the diff lock , there was also an automatic change to low range........
Going back the other way , coming out of diff lock brought that range change back
to high range ...(where the h/low switch was left )..
When going to use the diff lock, i would say make sure it is in low range first, that
saves worrying about that situation...........
If the driver was not aware of this, there could a rather rough change as the donk
and transmission struggled to keep up to things ............
. All these points could affect the life and reputation of the Low Range set up......
Maybe another reason why KW said some road trains were having problems
that were supposed to be driver related............
Not to mention the incorrect plumbing that occurred on a lot of these axles ..........
KW would not initially believe this .......blaming the diff problems on all sorts of things..........
But that is another story in its self.............
well that is what i think of things..........

...................Billy................

This brings my thoughts back to the Eaton(??) 3 speed rears.. This is where the intermediate speed was created by one rear in low and the other in high.. They must have created a stronger power divider to withstand the abuse. There were a lot of them in the States before the multi speed transmissions became popular. I forget how well they stood up. Obviously long periods in intermediate must have been hard on the power train.

.
.I might as well tell the bit about the plumbing problems............
In the early 70's i was at KW St Peters, Lansvale opened and i moved there.......
Also in the Lansvale area was R S Williams, a transport crowd that ran a service
up north , Mt Isa.Darwin etc ,etc,........
They bought a cab over KW, 350 Cummins ,12515 box, Eaton D/R 44's on Big 6 rsend.......
Right from the start it used to occasionally break the mounting bolts on the top rods
on the rear suspension ..........virtually unheard of at the time......and a real mystery.......
Then when only about 4 or 5 months old it had diff problems near Mt Isa.........
We got a local bloke to have a look, he said theres metal on both drain plugs .......
He seemed ok, so we said pull it apart and have a bo peep...........
Result was both diffs completely stuffed......We contacted Bayswater ,then the
shit fight started...........what caused this , got to be driver related, changing on the trot ......
went on and on............so it was decided to repair it and worry who paid at a later date........
The bloke rebuilds it, takes it for a run and rings us up saying theres some sort
of problem here cos the range change doesnt make any difference ,and with the diff lock in
there is rubber peeling off the drive tyres...........
He then says i think one diff is in high the other in low..........
Ok we says check the air plumbing ,and do what you reckon............
Rings us later in the day saying , yep ,that was the way it was, now all looks ok.............
Driver hooks all the trailers up and takes it for a gallop , says all seems ok
and away he went..........Hardly ever saw the truck after that ..........
So we thought , that explains the breaking bolts, one diff trying to climb over the other..
So when the truck was on the blacktop ,after coming off the muddy dirt, the diff lock
was still jammed in through the windup action.............So how many Ks it did like that
you can only imagine.....
Then ...who pays the bill ???? there was some arguements about that till another local
bloke was having problems with the diff lock jamming in................
That turned out to be the same plumbing problem..............
We checked two other local trucks, although they werent aware of a problem.............
Both were plumbed incorrectly.....So if the diff lock wasnt used , they werent aware
of the situation............
At the same time, none of the drivers noticed that high and low range were the same
speed , eng revs, etc
You know you dont have to know how a watch works to tell the time, ..but.......
a little bit of info doesnt go astray........ We will assume the drivers were just not aware how
things were supposed to operate............
Now .........how many other trucks , nation wide, had the same problem.............
Surely there must have been more..........
If the diff lock wasnt used much.........they might have spent their life with
one in low , the other in high.................and no body was any the wiser..............
Any way KW came to the party, BUT, never owned up to the fact what the trouble really was...........

Well thats about it ........a case of Ripley.....believe it or not..........

.......................Billy....................

I would imagine the performance was somewhat enhanced with both diffs in unison.