In engines use approximately 20% or one quart to each gallon of any plain motor oil, petroleum or synthetic.
In badly worn engines, use more up to 60% or 80% if necessary. In manual transmissions and transfer cases use 25% to 50%.
In differentials use 25% to 50%.
In badly worn or noisy differentials use 50% to 100%.
In industrial gear boxes use 25% to 50% for preventative maintenance and less power drain. If necessary use 50% to 100% to stop leaks and overheating.