This is the second gear 28 teeth as used on many 3-synchro Mini gearboxes. Introduced during the late 850 production and continued in use thru the "S" gearbox with the
22G1100 laygear. If you are inspecting your old gears be sure to check the engagement teeth, these are the small teeth on the end of the gear that takes all the abuse as you shift gears. While the large dirve teeth are typically very good, it's the engagement teeth that wear out. Also be sure to check the synchro land area of the gear. When you place a new synchro ring on the gear it should NOT bottom out.