Automotive Technology Chapter 44 Quiz

Name the 3 components that are added to a RWD vehicle to make it a 4WD vehicle.

Front differential & Axles Transfer Case Drive Shaft

What is the purpose of the interaxle differential?

The inter axle differential (also called a power divider) is an integral shaft in the forward axle. That shaft is the input for the forward axle and also the rear axle with a differential separating the input from the output allowing for a difference in speed between the front and rear axle.

What are the primary differences between a full-time and a part-time 4WD system?

When needed (usually beyond pavement) 4WD can be engaged. 4WD is used part of the time. When 4WD is engaged front wheels are powered as well - if the vehicle has manual hubs on the front wheels, they need to be locked first. 4WD "high", sometimes called high range, cannot be used on dry pavement with a "part time " system. For extreme situations 4WD "low"is available, it cannot be used on dry pavement either.4WD

How does a viscous clutch assembly work? Why is it used in a AWD systems?

one set of steel plates is splined internally to the clutch assembly hub, the second set of plates is splined externally to the clutch drum. the housing is filled with a small amount of air and special silicone fluid with purpose of transmitting force from driving plates to driven plates. when a difference of 8% exists between input shaft driven by driving axle the clutch plates shear silicone fluid. causes heat to build within the housing. causes silicone to stiffen and lock action between clutch plates. It help the vehicle not slip or lose traction.

When the plates of a viscous coupling (clutch) rotate at different speeds, the plates_____ the fluid.

shearing (cutting)

Describe the purpose of a viscous clutch.

takes the place of the interaxle differential. Improves mobility under difficult driving conditions. Operates automatically while constantly transmitting power to the axle assembly as soon as it becomes necessary to improve driving wheel traction.

What is the primary purpose of a transfer case?

transfers power from the transmission to the front and rear axles by means of drive shafts.

Briefly explain how a Haldex clutch works.

When both shafts are rotating at the same speed, there is no pumping action. When a speed difference occurs, the pumping starts immediately to generate oil flow. It is a piston pump, so there is a virtually instant reaction with no low-speed pumping loss. The oil flows to a clutch piston, compressing the clutch pack and braking the speed difference between the axles. The oil returns to the reservoir via a controllable valve, which adjusts the oil pressure and the force on the clutch package.

The transfer clutch in the all-wheel drive automatic transaxle takes the place of the________.

a. Transmission b. Reduction gears c.Torque converter d. Interaxle differential

What results from having different axle ratios on the front and rear of a 4WD vehicle when it is operating in 4WD?

a. poor handling on dry surfaces b. driveline windup c. mechanical damage to the driveline d. all the above