Sometimes when a particular product is dominated by a particular maker, the maker's name pre-supposes the nomenclature of the product - ie. 'Frigidaire', 'Jeep', etc. 'Frigidaire' became synonymous with refrigerator; 'Jeep' became synonymous with 4-wheel drive vehicle.
So for some, perhaps, an over-drive unit is automatically thought of by some, to be a 'Mitchell.
I too, like Mike, suspect that with a solenoid involved, the unit is a Borg-Warner, or similar over-drive unit - not a Mitchell.