It is widely understood that cold ambient temperatures negatively impact vehicle system efficiency. This is due to increased friction (engine oil, transmission, and driveline viscous effects), cold start enrichment, heat transfer, and air density variations. Although the science of quantifying steady-state vehicle component efficiency is mature, transient component efficiency over dynamic ambient real-world conditions is less understood and quantified. This work characterizes transmission efficiency utilizing transmission heating technologies over various drive cycles and ambient conditions. Dynamometer testing over hot and cold ambient temperatures was conducted for two vehicles utilizing transmission warming technologies, and one vehicle using pads to pre-heat the transmission. For the vehicles with transmission heating technologies, tests were conducted with the systems both on and off to compare gains in efficiency. Additionally tests were conducted with the last vehicle in which the transmission was pre-heated prior to running the drive cycles. For the urban cycle driven at +-7°C, the pre-heated transmission was shown to reduce consumption 2.5% over the cold transmission, while consumption for the US06 test was shown to be reduced by 7%. For +20oC tests, the pre-heated transmission was shown to reduce consumption approximately 1%, while minimal benefit was seen for the US06 cycle. Tests Further show the efficiency gains relative to production based transmission pre-heating efforts and put this into context relative to potential engine gains using waste heat to increase engine efficiency.