| Also known as | T1977 |
| Diagram | Fig. 9 — GEARBOX OUTER COVER AND LEVERS · ref 14 |
| Subsystem | gearbox |
| Listed in parts books | 1964–1970, 1974 |
SPRING COVER T100 SHIFT HOUSING
Spring cover for the T100 gearbox shift housing, part 57-1977, retains the spring in the outer cover shift mechanism.
57-1977 is the spring cover for the gearshift housing, shown in the parts book under GEARBOX OUTER COVER AND LEVERS. It's a small cover plate that sits over the spring inside the shift mechanism housing on the outer gearbox cover, keeping that spring retained and located where it belongs so the shift action works the way it's supposed to.
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You'll also see this part listed as T1977, which is the older letter-prefix number from before Triumph switched to the all-numeric part numbering. Same physical piece either way, so if your parts book or an old invoice shows T1977, that's this cover.
It shows up across catalog listings spanning the late 1960s into the early 1970s. It's a simple, inexpensive part to have in the toolbox if you're already in the gearbox outer cover doing shift mechanism work — not something that fails often, but easy to lose track of or damage when the housing is apart.
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