The front propeller shaft transmits rotating force from the transfer case to the front differential
when the transfer case is engaged. The front propeller shaft connects to the transfer case using a
splined slip joint.
One Piece Propeller Shaft Description
A 1 piece propeller shaft uses a splined slip joint to connect the driveline to the transmission or
transfer case.
Two Piece Propeller Shaft Description
There are 3 universal joints used on the two piece propeller shaft, A center bearing assembly is
used to support the propeller shaft connection point and help isolate the vehicle from vibration.
Propeller Shaft Phasing Description
The propeller shaft is designed and built with the yoke lugs (ears) in line with each other. This
produces the smoothest running shaft possible. A propeller shaft designed with built in yoke lugs
in line is known as in - phase. An out of phase propeller shaft often causes vibration. The
propeller shaft generates vibration from speeding up and slowing down each time the universal
joint goes around. The vibration is the same as a person snapping a rope and watching the wave
reaction flow to the end. An in phase propeller shaft is similar to 2 persons snapping a rope at the
same time and watching the waves meet and cancel each other out. A total cancellation of
vibration produces a smooth flow of power in the drive line. All splined shaft slip yokes are
keyed in order to ensure proper phasing.
Universal Joint Description
The universal joint is connected to the propeller shaft. The universal consist of 4 caps with needle
bearings and grease seals mounted on the trunnions of a cross or spider. These bearings and caps
are greased at the factory and no periodic maintenance is required. There are 2 universal joints
used in a one piece propeller shaft and 3 used in two piece propeller shaft. The bearings and caps
are pressed into the yokes and held in place with snap rings, except for 2 bearings on some
models witch are strapped onto the pinion flange of the differential. Universal joints are designed
to handle the effects of various loads and rear axle windup conditions during acceleration and
braking. The universal joint operates efficiently and safely within the designed angle variations.
when the design angles are exceeded, the operational life of the joint decreases.
Center Bearing Description
Center bearings support the driveline when using 2 or more propeller shafts. The center bearing is
a ball bearing mounted in a rubber cushion that attaches to a frame crossmember. The
2007 Hummer H3
2007 Driveline/Axle Propeller Shaft - H3