One-Piece Propeller Shaft Description
A one-piece propeller shaft uses a splined slip joint in order to connect the driveline to the transmission, or to
the transfer case.
Propeller Shaft Phasing Description
The propeller shaft is designed and built with the yoke lugs, or the ears, in-line with each other. This produces
the smoothest running shaft possible. A propeller shaft that is 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 from slowing down each time that the universal joint spins around. The vibration is similar to 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. Cancelling the
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 joint consists of 4 caps with needle
bearings and with grease seals. The caps and the seals are mounted on the trunnions of a cross or of a spider.
The bearings and the caps are greased at the factory. No periodic maintenance is required. Two universal joints
are used in a one-piece propeller shaft. Three universal joints are used in a two-piece propeller shaft. The
bearings and the caps are pressed into the yokes. The bearings and the caps are held in place with snap rings,
except for 2 bearings on some models. These bearings on some models are attached to the pinion flange of the
differential. Universal joints handle the effects of various loads and of rear axle windup conditions during
acceleration and braking. The universal joint operation is efficient and safe within the designed angle variations.
When the design angle is 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
in a rubber cushion that attaches to a frame crossmember. The manufacturer lubricates the bearing and seals the
bearing. The cushion allows vertical motion at the driveline and helps isolate the vehicle from vibration.
SPECIAL TOOLS AND EQUIPMENT
SPECIAL TOOLS
Special Tools
Illustration
Tool Number/Description
J 9522-3
U Joint Bearing Separator
2004 Hummer H2
2004 DRIVELINE/AXLE Propeller Shaft - Hummer H2