Patent ID: 7210294

Claim:
A hydraulic apparatus for driving at least one output axle, comprising: a housing forming a main sump and comprising at least one axle horn through which the at least one output axle extends; an expansion sump formed in the axle horn and extending along a length of the at least one output axle; an inner radial surface and an outer radial surface, both radial surfaces being formed within the housing and generally opposing each other; a seal member positioned within the housing adjacent to the axle horn and having an exterior radius mating with the outer radial surface and an interior radius mating with the inner radial surface; an arcuate fluid passage having an arc length formed between the exterior radius of the seal member and the outer radial surface of the housing; a first connecting passage formed between the main sump and the arcuate fluid passage; and a second connecting passage formed between the expansion sump and the arcuate fluid passage, wherein the first connecting passage and the second connecting passage intersect the arcuate fluid passage at two separate locations along its arc length to connect the expansion sump to the main sump.