| Also known as | T1971 |
| Diagram | Fig. 7 — GEARBOX SHAFTS, BEARINGS AND INNER COVER · ref 11 |
| Subsystem | gearbox |
| Listed in parts books | 1966 |
MAINSHAFT c/w THIRD & LOW GEAR
Gearbox mainshaft complete with third and low gear, Triumph part 57-1971 (aka T1971).
This is the mainshaft assembly for the gearbox, sold complete with third and low gear already fitted. It's a Triumph gearbox internal, part number 57-1971, which shows up in older parts books under the T1971 designation. If you're chasing this by the old number, it's the same physical part.
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The mainshaft is the heart of the gearbox cluster — the shaft that carries the gears riders shift through, splined and machined to hold the gear pairs and bushings in their correct running positions. Catalog listings tie this one to the gearbox shafts, bearings, and inner cover figure, so it lives inside the gearbox shell alongside the layshaft and selector mechanism.
Our catalog record for this one is thin on model-year specifics beyond a single year in the appearance history, so if you're matching this to a particular gearbox, best to check the part against what's actually in the case or give us a call before you order.
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