A system including a current module, a second module, and a temperature module. The current module is configured to determine an amount of current drawn from a power source by a hydraulic pump of a transmission based on a current signal received from a current sensor. The current signal is indicative of the current drawn by the hydraulic pump. The second module is configured to determine (i) a speed of the hydraulic pump based on a speed signal received from a speed sensor, or (ii) an output torque of the hydraulic pump based on the amount of current drawn by the hydraulic pump. The speed signal is indicative of the speed of the hydraulic pump. The temperature module is configured to estimate a temperature of a hydraulic fluid circulated by the hydraulic pump based on (i) the amount of current drawn by the hydraulic pump, and (ii) the speed or the output torque of the hydraulic pump. The second module is configured to adjust the speed of the hydraulic pump based on the temperature of the hydraulic fluid.