Clutches 4 and 3 slide along square guides a and b of input shaft 1. Gears 9, 10, 11 and 12 are keyed to output shaft 2 and are in constant engagement with gears 5, 6, 7 and 8 which rotate freely about shaft 1. When driving shaft 1 rotates, driven shaft 2 can have any one of four speeds for which clutch 3 is engaged to either gear 5 or 6 with clutch 4 in the neutral position, or clutch 4 is engaged to either gear 7 or 8 with clutch 3 in the neutral position. The corresponding transmission ratios are i₁₂=-z₉/z₅, i₁₂=-z₁₀/z₆, i₁₂=-z₁₁/z₇ and i₁₂=-z₁₂/z₈ where z₅, z₆, z₇, z₈, z₉, z₁₀, z₁₁ and z₁₂ are the numbers of teeth of gears 5, 6, 7, 8, 9, 10, 11 and 12.
$2852$CxG,SR$