Exam 44: Four- and All-Wheel Drive

Most all-wheel drive vehicles are based on an RWD platform.

Technician A says an interaxle differential can improve performance in poor traction conditions. Technician B says many 4WD vehicles use an interaxle differential in the transfer case to eliminate driveline windup during turns. Who is correct?

Usually the drive chain is replaced if the transfer case is being serviced.

Torsen units use planetary gears with teeth cut in a helical spiral pattern to limit wheel spin and alter torque distribution.

The interaxle differential on an AWD vehicle cannot be locked when the vehicle is driven on dry pavement.

Most passenger cars with 4WD are designed for the rigors of off-road driving, in which clearance over rocks and debris is needed.

Explain the difference between four-wheel drive (4WD)and all-wheel drive (AWD).

An interaxle differential lowers performance in poor traction conditions.

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

A typical four-wheel drive truck has a longitudinally based engine, a manual or automatic transmission, and a transfer case.

Technician A says in a full-time AWD transmission/transfer case, the hydraulic clutch that controls slippage in the 4WD system is controlled by inputs from the ABS wheel speed sensors. Technician B says some full-time AWD transfer cases can lock the differential so that the front and rear driveshafts must turn at the same speed. Who is correct?

Automatic locking hubs are unlocked when ______.

Technician A says an all-wheel drive vehicle uses a differential at both axles. Technician B says some four-wheel drive vehicles use an interaxle differential. Who is correct?

Describe the operation of a viscous clutch.

Some 4WD vehicles that have been adapted from a FWD format use a(n)____________________ take-off to transmit torque to the rear driveline.

Name the three main driveline components that are added to a 2WD vehicle to make it a 4WD vehicle.

What is the function of locking hubs?

A passenger car equipped with a 4WD system weighs approximately 170 pounds (77 kg)more than a similar 2WD car.

All-wheel drive vehicles may be switched to two-wheel drive by activating the mode switch.

Four-wheel drive operation modes are being discussed. Technician A says 4-low, as compared to 4-high, increases wheel torque. Technician B says 2-low is available on most 4WD vehicles. Who is correct?