Internal Gearbox 1275cc (G-AN4, G-AN5, H-AN9, H-AN10, A-AN10)

The components listed below are those fitted to all original 1275cc Sprite & Midget gearboxes, which used what were termed ‘B’ type gears. However, a number of different gearboxes and sets of internal components have been offered as replacements over the years. Please read the info note below before ordering parts.

So which Gearbox is Fitted to Your Car?

You definitely won’t, of course, find a Mini transverse unit, and it is most unlikely that any one would have fitted a smooth case gearbox: there are too many modifications required to fit what is essentially an inferior gearbox to the 1275cc engine. Plus, ‘spare’ smooth case gearboxes have been thin on the ground for many years. Therefore, you will have a ribbed case gearbox, with one of three distinct gear sets in it :

1. Minor/A35 van/A40 MkII ratios.

2. Sprite/Midget ‘A’ Type gears.

3. Sprite/Midget ‘B’ Type gears.

The principal way to ascertain which of the three you have is to open the gearbox and look at the laygear, which is only just visible behind the mainshaft gear cluster. Normally the part number is stamped on the waist between the largest and second largest gears: 22G83 for a Minor gear set, 22G76 for an ‘A’ Type Sprite/Midget gear set and either 22G232 or (more likely) 22G1100 for a ‘B’ Type Sprite/Midget gear set. To further confirm whether you have a Minor or Sprite/Midget gear set, count the number of teeth on either first, second or third gear, plus the number of teeth on the corresponding cog on the laygear. Divide the former number by the latter and you will have the ratio of that gear.