The invention comprises a method, an article, and a control system for controlling a powertrain having a main and an auxiliary hydraulic pump, with each pump operative to supply hydraulic fluid to a hydraulic circuit of the transmission. It includes determining a main pressure and a desired main pressure, and controlling the auxiliary hydraulic pump. Determining a main pressure in the hydraulic circuit comprises estimating hydraulic pressure. The auxiliary pump is controlled to an operating speed. Control of flow from the auxiliary and main pumps can comprise an exclusive `either-or` flow, or a blended flow.