I use it in my Harley and high mileage vehicles. It's a friction reducer, and seems to increase the viscosity some. Can't see why it wouldn't work in any gearbox. I would probably avoid using it with any kind of wet clutch setup. Mike
Spindle oil is not something to be increasing the viscosity of, may cause excessive heating and bearing failure. Use the correct spindle oil recommended bu the manufacturer; in the case of waylube, ditto. Years ago, STP was the big thing, this is just more snake oil.