MK1, MK2, S-Type Gearbox

Hi folks

Trying to identify the following Gearbox in these photos. The top is missing. I inherited the parts from my late Father-in-law, mechanic.

Serial Number GBN 61078 JS

I understand from some good folk elsewhere that it could be a MK1, MK2 or possibly S-Type 2.4 or 3.4

I also have an Auto Transmission for something similar in a another post.

Any help would be appreciated. Thanks in advance.


It is exactly as you describe, a Mk1 early Mk2 or S-type box with overdrive and shaved gears.

Given the number most likely it’s off a Mk2.

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Maybe an early S Type with the Moss gearbox but not a 1965 or later with full syncho and compact overdrive shown here,

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Here is a close serial number (GBN 63148JS), saying it is from Mk1 Mk2 w OD:


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Thanks guys much appreciated.

Inform me, what exactly are shaved gears?

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“Gear shaving is a free-cut gear finishing operation that removes fine gears. A lot of metal can be gotten from the working surfaces of the gear teeth. Its purpose is to correct errors in helix angle, index, tooth profile and eccentricity. The process can also improve tooth surface finish and eliminates the danger of load concentration at the tooth end during use through the crown form. Gear shaving provides the modifications of form to reduce gear noise. These improvements can also increase the load-carrying capacity, safety factor and service life of the gears.”

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Thanks, KopiK, I never knew any of that.

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Great information @KopiK thank you. I’m assuming it’s only logical that all gears are now shaved? Pardon my lack of tech!