Smaller of the 2 shims at the ends of the laygear on the layshaft. These are sized accordingly and fit the first gear end.
For alternative sizes, see:
DAM3180 - .121”-.123” (3.07-3.12mm)
DAM3181 - .124”-.126” (3.1-3.20mm)
DAM3182 - .127”-.129” (3.22-3.27mm)
DAM3183 - .130”-.132” (3.30-3.35mm)
