Caterpillar D8 spec-sheets

As a collector of Caterpillar spec sheets, I take things quite far—I even organize them by number.

For the Caterpillar D8, for instance, I have spec sheets with the following numbers: 1823-53 A, B,- D, E, F, G, H,- - K, L, M, N, O, P, Q, - S, T, U, - and W.

This means I am missing 1823-53 C, I, J, R, and V.

I scanned a Dutch-language spec sheet from a fellow collector, which consequently bears a different number: 500-850.

On closer inspection, all my other spec sheets show a single gearshift lever, whereas this Dutch spec sheet shows the D8 with two!

Does anyone have an explanation for this?

In my collection, the two-lever gearshift configuration appears only on the spec sheets for the dozer blades.

Could this 500-850 number be 1823-53 O or V?

Hi Ad, I think this answer on your Facebook query is correct;

‘The two lever is the later 2u model with constant mesh transmission/pressure lubricated and the 2gear lever for forward/reverse direction known as the “Johnson bar”‘

Hi, Quad

The early D8s, 1H, 8R and early 2U series all had what was commonly called the 'slide bar transmission' where you had to slide a single stick sideways through a slotted gate to select the gear you wanted, both forward and reverse gears on the one stick.

Somehwere during the 1950 production of the 2U series D8s, they changed the transmission to the 2 stick version with the forward/reverse lever - 'Johnson bar' and a second stick to select a gear for speed, 5 forward gears and 4 reverse.

At the same time, Cat also introduced what became known as the 'hard nose', the front end radiator surround designed to carry a 'dozer blade on a single center-mounted sheave block. As I understand it, prior to this upgrade, having a cable dozer fitted required that a frame be attached to the tractor main frame rails adjacent the radiator to carry a sheave block above the radiator.

These machines can usually be identified either by braces from the main frame rails supporting the radiator or by side plates doing the same job while the 'hard nose' on the later machines is a one-piece cowl made from about 10-mm plate starting from the main frame rails on both sides and extending right over the top of the radiator with a removable 2-piece punched grille in front of the radiator similar to that shown in your fifth post with the 8SR blade.

I am open to correction on this.

Just my 0.02.

In the slide bar transmission second gear is directly opposite of high reverse and low reverse so it works very much like a johnson bar in production work. First gear is painfully over to the left. With a johnson bar if you want high reverse you need to shift the main stick too.

Hi, 8C 361.

Yes, you did have to shifts both sticks if you were travelling forward in first and wanted to reverse in second. But it was almost a circular motion, push the 'Johnson bar' forward into reverse and grab the main stick to pull it back into second on the return, a little more complicated if you waned a higher gear than second.

I found it very easy to get used to, especially after coming from a 2U D4 where you had to reach down between your knees to do any gear changing.

Just my 0.02.