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Gearboxes to the A-series
Whats inside Gearboxes to the A-series ?
(sources :
Mini Life, Mini Club Swedens mag issue 2 1990
Mini Marcos Owners Club Magazine - Issue 34)
A-box : manufactured before 1964
B-box : all other boxes
1968 came synchromesh on 1,2,3 and 4.
Rodchange came in dec 1972-jan 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 .)
more------>---->
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Boxes Ratios Car Year Clutch
1 2 3 4 F/D
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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
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A-box 3.200 1.916 1.357 1.00 3.765 997cc Cooper 1961 Same clutch
3.444 bonded
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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
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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
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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
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A-box 3.200 1.916 1.357 1.00 3.765 997 now 998cc 1964 Bonded
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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
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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 1867
3.525 2.218 1.433 1.00 3.647 1300 1967
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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
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B-box as above 3.330 2.094 1.353 1.00 3.444 1275 Gt 1970/1 Diaphragm
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B-box with new rod ALL RATIOS REMAIN THE SAME ON ALL MODELS 1972/3 Diaphragm
gear change AS SHOWN ABOVE
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New B-box 3.525 2.218 1.433 1.00 3.444 Clubman now 1975 Diaphragm
1098 cc
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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
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Last modified: 20 April 1996
Copyright ©
Micke Pettersson
Tiundagatan 39
S-752 34 Uppsala
Sweden
Phone: +46 18 50 00 93
mikael.pettersson@tsl.uu.se