| Also known as | T4364 |
| Diagram | Fig. 11 — GEARBOX INNER COVER AND SELECTORS · ref 22 |
| Subsystem | gearbox |
| Listed in parts books | 1971–1974, 1976–1980, 1983, 1985 |
Selector fork - mainshaft 4th gear
Selector fork for 4th gear on the mainshaft side of a Triumph five-speed gearbox, PN 57-4364 (formerly T4364).
This is the selector fork that shifts 4th gear on the mainshaft side of the gearbox, part number 57-4364, also catalogued under the older T4364 designation. It's a gearbox internal, showing up in the inner cover and selector mechanism drawings as well as in the five-speed gearbox parts lists, so this fork is tied to five-speed applications rather than the four-speed cluster.
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The fork itself rides in a groove on the selector drum and engages the sliding gear on the mainshaft, moving it into position when you work the gearchange. It's a wear part - the fingers that contact the gear can thin out over years of shifting, and a worn fork is a common cause of a gearbox that jumps out of 4th or feels vague going into it.
We don't have a lot more written down on this one beyond where it sits in the gearbox drawings. If you're rebuilding a five-speed box and pulling the selectors out for inspection, check the fork fingers for wear against the mating gear before you put it back in - call the shop if you want to talk through what you're seeing.
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