Patent ID: 6997841

Claim:
An inter-axle differential assembly for a vehicular power transmission unit provided with a supply of lubricant, said inter-axle differential assembly comprising: a differential input shaft; a differential output shaft; a differential gearing, said a differential gearing including: a first side gear and a second side gear arranged coaxially relative to said input shaft and rotatable relative to said differential input shaft, said first side gear is drivingly coupled to said output shaft; a differential spider drivingly connected to said input shaft; and a plurality of pinion gears rotatably mounted to said differential spider and drivingly engaging said first side gear and said second side gear to allow differential rotation thereof; a dedicated lubrication pump for lubricating components of said differential assembly, said pump mounted between said input shaft and said output shaft, wherein said pump generates lubrication flow whenever differential action between said differential input shaft and said differential output shaft occurs, said lubrication pump including a rotor non-rotatably coupled to said input shaft and an impeller positioned within said first side gear, wherein said rotor is rotatably disposed within said impeller and is operative upon rotation with respect to said impeller; said lubrication pump being axially spaced from both said differential input shaft and said differential output shaft; a hydraulic fluid suction passage providing an inlet fluid communication passage between said supply of lubricant and an inlet port of said lubrication pump; and a gallery of fluid passages supplying said lubricant for lubricating said components of said inter-axle differential assembly; said gallery of fluid passages fluidly connected to an outlet port of said lubrication pump.