DIFFERENTIALS and DRIVE AXLES Chapter 7 Page 137 Classroom Manual Page 247 Lab Manual

OBJECTIVES Describe the purpose of a differential. Identify the major components of a differential and explain their purpose. Explain the need for drive pinion bearing preload. Describe the difference between hunting, and nonhunting gear sets. CBC AUTOMOTIVE RK

OBJECTIVES Explain the purpose of the major bearings within a differential assembly. Describe the operation of a limited-slip differential. Describe the construction and operation of a rear axle assembly. Identify the two major designs of rear axle housings.

INTRODUCTION Solid rear axle (with leaf or coil springs.) IRS (Independent Rear Suspension) Hypoid gear set (pinion below centerline) FWD (helical cut ring and pinion) Differential (allows different wheel speeds) CBC AUTOMOTIVE RK

Leaf Spring Suspension SOLID REAR AXLE Coil Spring Suspension

HYPOID GEAR SET Pinion centerline is below Ring Gear centerline. CBC AUTOMOTIVE RK

FWD HELICAL CUT RING & PINION Pinion can be called the Main shaft, Intermediate shaft, or Transfer shaft.

DIFFERENTIAL Allows each drive wheel to travel at different speeds, and different distances.

FUNCTION and COMPONENTS Pinion mounted on two tapered bearings. Differential case mounted on two tapered bearings 90 degrees to the pinion. Pinion and differential bearings are PRELOADED no play. Differential assembly is case, side gears, spider gears, and pin. CBC AUTOMOTIVE RK Page 139 C

DIFFERENTIAL OPERATION Allows drive wheels to operate at different speeds, and travel different distances. When traveling straight ahead both wheels rotate at the same speed and same distance. CBC AUTOMOTIVE RK Page 140 C

AXLE HOUSINGS Two types of differential carriers: Integral carrier Salisbury or Hotchis Removable carrier Third member CBC AUTOMOTIVE RK Page 145 C

DIFFERENTIAL GEARS Two types of RWD differential gears: Spiral Bevel Ring & Pinion centerlines intersect Hypoid Pinion centerline is below Ring gear centerline Hypoid lube required! Drive - Coast CBC AUTOMOTIVE RK Page 146 C

GEAR RATIO Number of INPUT gear revolutions to equal One OUTPUT revolution. Any # >1:1 = Underdrive 1:1 = Direct drive Any # <1:1 = Overdrive Driven Drive CBC AUTOMOTIVE RK Page 148 C

DETERMINING FINAL DRIVE Decipher the “code” On the tag under a cover bolt. Differential housing tube. Door post. CBC AUTOMOTIVE RK Page 149 C