[Mac VP]

There’s an honest effort to provide some help here in this thread so I don’t want to criticize. Perhaps a bit of clarification will be helpful on a couple points.

1) The early mainshafts (32-38) did use a small pin, along with a tiny spring, to help secure a sliding lock key under the early 2nd gear. His particular gear set is a 39-45 type. On those mainshafts Ford placed a 1/8” diameter pin in a matching hole, just ahead of the splines for the low/reverse gear. I’ve personally encountered hardened and non-hardened pins here. The non hardened pins are fairly easily drilled out. The hardened ones can only be drilled out with a special tungsten bit. Use a drill press and a press vice with a rag or thin pieces of wood to clamp the shaft in the jaws of the vice. Use cutting oil and gentle pressure and plenty of patience to drill out the pin. It helps to create a center divot in the pin. We have the factory replacement pins but you can make them yourself easily.

2) The shape of the 7102 second gear did not change in 1951 so the “diamond tip” reference really doesn’t apply here. What changed was the overall diameter. The 81A-7102 gear (used from 1939-50) was roughly 3.03” in diameter. The 1A-7102 gear (used from 1951-55 and newer) was roughly 3.13” diameter. Although they look and measure nearly identical, they are not interchangeable.