Whilst there were subtle internal changes to the gearbox throughout production they underwent a significant design change in 1957. The prop shaft changed from a sliding type to a bolt on type. The mainshaft, rear housing, oil seal arrangements and other parts were changed.
The Clutch thrust bearing was also changed from a carbon thrust type to a roller bearing.
The bolt on propshaft type gearbox is considered the better box and many cars have been retro fitted with them.
Please read our descriptions carefully and compare our photos with the parts coming off your car before ordering. If in doubt please email us for advice.
Standard issued the following guidance for Dealers advising the chassis number change over point.
Standard 8 – CS 85754.
Standard 10 & Companion/Commercial Derivatives – BE 99193