Saginaw box

[HK1837]

As above the Saginaw was a 1950's-1960's product, started life as a 3spd just like the aussie box did. Used behind small V8 and 6cyl. Became a 4spd in the later 60's. High power engines used the 3spd and 4spd Muncies. The 4spd Saginaw and Muncie replaced the T10 (which itself was a modified T85 3spd). Once big power big blocks finished the Muncie was shelved and GM used the T10 again now made by Borg Warner.

Gene, does the Saginaw you have, have a side shifter mount like the photo above or does it have a smooth extension housing? Holden used the Saginaw in lots of applications:

HK-HT 6cyl HD option.
HK-HG standard 4spd in commercials.
HK 307 and 327.
HT-HG standard V8 4spd manual.
HT-HG 350.

There were 2 x different ratios, but the boxes were identical externally (no longer input shafts for V8, that silly idea is a Holden anomoly).

[Dr Terry]

The 4spd Saginaw and Muncie replaced the T10 (which itself was a modified T85 3spd). Once big power big blocks finished the Muncie was shelved and GM used the T10 again now made by Borg Warner.

The T10 was always made by Borg Warner. It was the 4-sp of choice for GM, Ford & Chrysler in the USA, before the advent of their own Saginaws, Muncies, Top Loaders & New Process gearboxes.

The later financial structure is a bit hazy, but basically Borg Warner took over the Muncie factory (or GM took control of BW, whatever), but the end result was that the best features of the Muncie & BW T10 were combined to become the 'Super T10'.

The Super T10 was arguably the best US 4-sp of the era, with both Holden & Ford using it behind their respective engines in the later Group C time.

Dr Terry