Gearbox Information A Series Gearbox Information A-box : was manufactured before 1964 B-box : all other boxes In 1968 came synchromesh on 1,2,3 and 4. Rodchange came in December 1972 /January 1973 but steeljoints came later 1973 Castnumber on front of the gearbox: 22A 363 Early 850 22G 68 A and B 850, 998,997 and 998 Cooper 22G 190 970 and 1071 A and B 22G 333 970 and 1275S B 22A 1128 3-sync b , not S 22G 1128 4-sync To get low rpm at a speed you got to have low nr on F/D.( compare a Mini 1000 ,3.444, with a Mini 850 , 3.765, the 850 has a higher rpm .) Boxes Ratios Car Year Clutch 1 2 3 4 F/D 4-speed with synchro 3.627 2.172 1.412 1.00 3.765 Mini 1959 3 coil on 2,3,4. A-box 3.627 2.172 1.412 1.00 3.765 Traveller 1960 spring Fitted with constant 3.627 2.172 1.412 1.00 3.765 Countryman 1960 clutch load conical sphere 3.627 2.172 1.412 1.00 3.765 Van 1960 7 1/2 in dia synchro 3.627 2.172 1.412 1.00 3.765 Pick-up 1961 A-box 3.200 1.916 1.357 1.00 3.765 997cc Cooper 1961 Same clutch 3.444 bonded A-box fitted with 3.627 2.172 1.412 1.00 4.13 1100 1962 Same clutches baulk ring synchro. All ratios remain the same on Mini models 1962 A-box as above 3.200 1.916 1.357 1.00 3.765 Cooper 1963 Bonded clutch 3.200 1.916 1.353 1.00 3.444 Cooper S 1071 1963 A-box with close 2.570 1.780 1.242 1.00 3.765 Cooper 970 1964 Bonded ratio gears 2.570 1.780 1.242 1.00 3.444 Cooper 1275 1964 3.938 Cooper diff 1964 4.133 options 1964 A-box 3.200 1.916 1.357 1.00 3.765 997 now 998cc 1964 Bonded Basic design change ALL RATIOS REMAIN THE SAME ON ALL MODELS 1964 New diaphragm and box now B-type. AS SHOWN ABOVE spring clutch Wider gears and helix change B-box 3.627 2.172 1.412 1.00 3.444 Mini 1000 1967 Diaphragm 3.330 2.094 1.353 1.00 3.647 1300 GT 1967 3.330 2.094 1.353 1.00 3.647 MG 1300 1967 3.330 2.094 1.353 1.00 3.647 Riley Kestrel 1967 3.525 2.218 1.433 1.00 3.647 1300 1967 B-box now with new 3.525 2.218 1.433 1.00 3.765 All 848 Minis 1968 Diaphragm synchromesh on 1,2 3.525 2.218 1.433 1.00 3.444 Mini 1000 1968 3 and 4. 3.330 2.094 1.353 1.00 3.444 Cooper S 1968 3.525 2.218 1.433 1.00 3.444 Clubman 1969 3.330 2.094 1.353 1.00 3.647 1275 GT 1969 3.525 2.218 1.433 1.00 4.133 1100 1969 3.525 2.218 1.433 1.00 3.647 1300 1969 3.330 2.94 1.353 1.00 3.647 1300 GT models 1969 B-box as above 3.330 2.094 1.353 1.00 3.444 1275 Gt 1970/1 Diaphragm B-box with new rod ALL RATIOS REMAIN THE SAME ON ALL MODELS 1972/3 Diaphragm gear change AS SHOWN ABOVE New B-box 3.525 2.218 1.433 1.00 3.444 Clubman now 1975 Diaphragm 1098 cc B-box with rod 3.525 2.218 1.433 1.00 4.133 Allegro 1100 1973 Diaphragm change 3.525 2.218 1.433 1.00 3.938 Allegro 1300 1973