2 weeks to change a gearbox washer must be somthing of a record.

In theory gearbox drain plug washers, whether aluminium or copper, should be changed every time the oil is drained. They work by crushing and would harden after use. Even though you may get away with re-using them it is not recommended. Using silicon gasket cement or somesuch is something that should not be necessary but perhaps is justified if no replacement washer is available.

Peter

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