Speedometer Part ID Needed
 

Hi All

Picked up another dead Ford instrument panel recently and hanging off the Stewart Warner speedometer was this device. I thought at first it was a converter to couple a speedo with an external thread cable coupling to an internal one but then the lever on the top appears to change the speed ratio. Its like a small gearbox. It is Stewart Warner manufacture.

What is it?

Bob

Ratio changer
 

It's fitted to vehicles with Eaton two-speed rear diffs. The little lever on the side is linked to the Axle shift, so that when you change the axle ratio, the speedo will still be accurate.

Ratio Changer
 

Thanks Tony
I made a bet with myself which was the "The Font of Knowledge" Tony would give me the answer.
Next question - what were the typical trucks, that we are interested in, that had Eatons fitted?
Bob

Sometimes, you buggers know more than is good for you... :eek:

Know It Alls
 

Hi Sunray Jifferoo
Yes we have our gurus here, but as I've said before MLU is full of gurus from throughout the globe and this forum is the perfect meeting place of the minds.
But of course Oz having most of the world's CMPs, the best built Carriers (and Keefy) , we can't go wrong.
Salesman Bob

Eaton two speed diffs
 

The most common truck fitted with an Eaton two speed Axle (from an Australian Military Vehicle point of view) was the Dodge T110-L5 (3 ton Dodge MCP). I'm pretty sure that the one bought by a certain SA collector from One Tree Hill had one of these fitted 'cos I had a good crawl around it before it went west.:p
Eaton Two speed axles were fairly common on Commercial trucks of the '30s, '40s and '50s and were also available of Fords, Chevs and Inters and some were fitted "Aftermarket" to a variety of British trucks. Some of the MCP Ford and Chev 3 tonners got them, too. I'm actually surprised that they weren't considered in place of a transfer case for Carriers or the Tracked Truck. They have a high ratio somewhere inthe vicinity of 6:1, reducing to 8:1.
Keefy might still have some of his Dodge T110 service manuals to show how the Axle selector worked in conjunction with the speedo reducer.

602
 

Didn't the 602 cmp trucks also have the eaton two speed diff
greg

Re: Eaton two speed diffs
 

The books I have are the driver instruction ones for the T 110-L-5 which do mention the Eaton axle but only how to use it from driver perspective (don't try to coast with it in neutral as SEVERE DAMAGE MAY RESULT) but nothing as technical as how the speedo adapts.

I still have some of these books available if anyone is interested.

Speedo Reducer
 

Tony
Once again you are correct. Had the One Tree Hill collector crawl around his three tonner Dodge today, and guess what he found. Yes one was hanging off the speedo. Now we know of two here in SA. It even had some of the operating cabling attached but was cut off at the firewall. There's no donk or tranny so the diff change lever was missing. Anyway, problem solved.
Bob