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

2. 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
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3. 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.

4. 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)
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5. Leaf Spring Suspension
SOLID REAR AXLE
Coil Spring Suspension

6. HYPOID GEAR SET Pinion centerline is below Ring Gear centerline. CBC
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7. FWD HELICAL CUT RING & PINION
Pinion can be called the Main shaft, Intermediate shaft, or
Transfer shaft.

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

9. 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.
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Page 139 C

10. 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.
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Page 140 C

11. AXLE HOUSINGS Two types of differential carriers: Integral carrier
Salisbury or Hotchis
Removable carrier
Third member
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Page 145 C

12. 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
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AUTOMOTIVE RK
Page 146 C

13. 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
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Page 148 C

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