BMC

BMC 3-synchro 4-speed

From the Gearbox Wiki, the reference for people who still shift their own.

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BMC 3-synchro 4-speed is a manual gearbox from BMC. The Society has 3 vehicles on file with it, 3 with a source we opened and 0 still leads.

MG

Vehicle	Years	Shift pattern	Gearbox source
MG MGB Roadster / GT (3-synchro 4-speed, first gear not synchronized) 4-speed, optional Laycock D-type overdrive ^[1]	1962-1965	4 speed, reverse bottom left	Corroborated
MG MGB Roadster / GT 4-speed ^[2]	1966	4 speed, reverse bottom left	Corroborated
MG MGB Roadster / GT (3-synchro 4-speed, first gear not synchronized) 4-speed, optional Laycock D-type overdrive ^[3] Applies to: Cars built before the 4-synchro box	1967	4 speed, reverse bottom left	Corroborated

Caveats and conflicts (1)

Retailer. MGOC Spares: 'From 1962 to 1967, the MGB used a 3-synchromesh gearbox without synchronisation on first gear'. [link]
Retailer. MGOC Spares MGB gearbox page: "From 1962 to 1967, the MGB used a 3-synchromesh gearbox without synchronisation on first gear"; Wikipedia MGB: based on the MGA gearbox. [link]
Retailer. MGOC Spares: 3-synchro box 1962 to 1967, 4-synchro box 1968 to 1980. [link]

Categories: Gearboxes | BMC

This page was last edited on November 11, 2026. Gearbox codes change by year, engine and market. Send a correction.