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Shop/Category/Fig. 10 — GEARS — SHAFTS — SELECTORS — STARTING MECHANISM/Sprocket – gearbox final drive (18T)
Sprocket – gearbox final drive (18T)
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Also known asT4398
DiagramFig. 10 — GEARS — SHAFTS — SELECTORS — STARTING MECHANISM · ref 53
Subsystemgearbox
Listed in parts books1972–1973

Sprocket – gearbox final drive (18T)

18-tooth gearbox final drive sprocket, part 57-4398, also known as T4398.

PN · 57-4398

This is the gearbox final drive sprocket, 18 tooth, off the mainshaft end of the gearbox. It's what the primary chain or drive line picks up power from once it leaves the layshaft and mainshaft gear cluster, so it's a wear item worth checking whenever you've got the gearbox apart. Catalog records show it under the T4398 legacy number as well as the current 57-4398, same physical part either way.

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Our catalog rows for this one show up in the gearbox shafts and gears figures, including the five-speed T150V gearbox layout, with appearances running 1972-1973. If you're rebuilding a box from that era or matching up a sprocket that's chewed or worn hooked at the tips, this is the number to check against what's on your bench.

We don't have a lot more written down on this one beyond the tooth count and where it sits in the gear train. Give us a call if you want to confirm it matches your gearbox before ordering.

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PN 57-4395 · Goes with this
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