ATKINSON

Moved the old girl of the tray today and parked her where she will sit till i drive her out. I pulled the spare diff off and noticed the splines are finer, so there useless to me. If anyone wants them it's there's, i'll hold on to the housing for a bit in case i need bits of it. I'm hoping i can find an axle, if i cant i'll get 1 made if it doesn't cost to much. I'm sure it,s got a diff lock, there's a air switch on the dash but the writing is long faded. But it's where you say it is Stephen.
The dash has was replaced with Acco gauges thanks to some under age vandels but being only sheet metal with holes in it making a new 1 wont be to hard, thanks for the pic's there a great help.
Also thanks for the positive feed back and all the info and advice, it's a great help. I'll keep you posted and add photo's as i go along.

Hi JnrMack, that switch is either diff lock or deep reduction (in the hub or the front of the diff), and maybe the diff is the same kirkstall as mine in the ERF & I need a new one, or maybe not. I heard Atkinson sometimes used them. Can you post some pics & get the plate details off the diff housing at the back? Mine are on a brass plate, which I hope the kids haven't stole from yours for the 10cents worth of brass.
I'm not the most knowledgable expert but this may tell you: below is a pic of the front input of my first diff in the bogie. That large 'can' shape on the front is the deep reduction that I can engage if I want a real crawler gear. If your single kirkstall has that then that switch is definately the deep reduction. That's about all I can help you with at the moment. (please forgive the coal dust everyone, I only just got it & haven't even cleaned it.)

other pic is of my 2 switches. You can see that if the writing is rubbed off you couldn't tell them apart. My diff lock & deep reduction are both air powered (I think) which means it's no good flicking the switch & lifting the back axle & turning the wheels to see if the switch activates diff lock as it won't come on anyway unless the air is up. could try stick a compressor in the air line. I'll leave it to cleverer folk to tell you how to work it out as i don't know. Also pictured is my diffs, try see if your single or the spare are the same kirkstall as my pair?
Mine are bogie Kirkstall T48 (according to Rod & the other ERF fans in the UK) with 5.65 ratio & diff locks & deep reduction on the input on front of first one for when I want to win a "tractor pulling comp" LOL. I may have spare diff parts in 6 weeks if all goes well?
Still love the compact look on your new Atki

SHS - Just to clear up your misconceptions .. the "can" at the front of your front diff (in a tandem drive) is known as the power divider, inter-axle diff, or third diff.

This "can" holds a compact set of gears that comprises a simple, lockable, open-centre differential .. and the gearset in the power divider also splits the incoming drive into two, with one drive going through gears to the front diff .. and the other drive going to the rear diff, via a shaft that runs from the power divider, through the top of the front diff housing, to the rear tail shaft (also sometimes called the jackshaft) and into the rear diff.

It's difficult to explain the setup precisely in words, I'll post an exploded view if I can find one.

The "diff lock" switch operates an air solenoid that locks the third diff in the power divider, so that both drive outputs from the power divider are locked into rotating at the same speed.

When the power divider is unlocked, the drive outputs can turn at different speeds, exactly as axles and wheels do in a normal rear axle.
So .. if you get bogged with your tandem drive truck, and an unlocked power divider, the drive axle (front or rear) with least resistance will spin .. and the wheel with least resistance, on that axle with least resistance, will spin. Thus, in this situation, only one dual wheel out of all four, will spin, as all three diffs are operating.

Locking the third diff in the power divider, via the air switch, means that output drive from the power divider is even to both front and rear diffs, and both front and rear diffs turn at the same speed and with the same power input.
This means you get both front and rear axles driving with the same even power input, instead of only one axle taking all the power. With a bogged truck, and a locked power divider, you're doubling the drive effort from the duals, and at worst, you will see one wheel on each axle spinning in the mud.

The "deep reduction" switch is an extra low gear in the Road ranger trannies, operated by an air solenoid. This switch has nothing to do with diffs, it's a transmission gear selector switch.

Jnr

I was just talking with a mate who got a fair bit of stuff from an old transport company who has all but shut down in Sydney. They ran Fodens with a few Atkinsons and thornycrofts. Up until 2 months ago they had a number of diffs stacked in their warehouse - complete hub to hub. I saw these 8 months ago and there must have been 5-20 complete units there. PM me if you are interested and I'll do some homework for you.

Hi Jnr Mack

Onetrack is completely right about those switches, the lefthand switch in the photo is for the deep reduction in a 15-speed Roadranger gearbox, it is definitely nothing to do with the diff and the other switch is for the power divider which is the "can" in front of the front diff.

Onetrack's explanation explains things exactly (Well done, Onetrack!) and I will guarantee he is correct, take it from me, an old Atkinson and ERF driver.

G'Day JnrMack, Nice truck mate,good find.Looks like it may have led a charmed life.

Here's one almost the same working with Metro Dairys in 1978.Gardner powered,but a little
bit longer in the wheelbase.What about the tanker it's pulling ?That's a real gem on its own.Pictured near Seymour.


R/

JnrMack,

May I also join the well wishers and ask a question: I noticed there were two styles of Aussi-built Atki cabs, yours and a later one - what's the reason for the change? Is the early cab fixed?

Cheers,

T

There were three versions of the fibreglass cab built by Reinforced Plastics, Jnr has the MK1 version and these got a tilt option about 1970. Later Mk2 and Mk3 versions had a set forward front axle and were tilt and sprung at the back mounts.

Thanks for the reply Pete - I actually think this early glass cab is very good looking, better looking than the Pommy cabs...

Cheers,

T

The factory in 1975,at first is a Defender.