| Also known as | AA117, E3975 |
| Diagram | Fig. 1 — CRANKSHAFT AND CONNECTING RODS · ref 20 |
| Subsystem | engine bottom |
| Listed in parts books | 1960–1974, 1976–1977 |
LOCK TAB WASHER ALTERNATOR ROTOR
Lock tab washer for the alternator rotor nut, keeps the retaining nut from backing off the crankshaft.
This is the lock tab washer that sits under the nut holding the alternator rotor onto the crankshaft end. It's a small stamped washer with a tab that bends over to keep the rotor nut from working loose once it's torqued down. Also known in older parts books under the E3975 and AA117 numbers, this same washer turns up across a long run of catalog entries for crankshaft and timing gear assemblies.
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It's a one-time-use kind of part in practice - once you bend the tab over to lock the nut, it's not something you want to fold back and reuse when you pull the rotor again. Cheap enough insurance to just grab a fresh one whenever you're in there.
We see this washer listed across crankshaft, connecting rod, and timing gear figures going back to 1960 and running through 1977 in the catalog record, so it's been a long-standing fitment across a wide span of production. If you're not sure which nut and washer combination your rotor uses, check your parts book or give us a call before ordering.
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