awd?
awd?
Freshman User
Joined: Sep 2007
Posts: 28
Likes: 0
If it's like my '01, it should be A4WD not AWD. It means Automatic 4-Wheel Drive. You are only driving with 2-wheels until it is sensed that a wheel is loosing traction, then the 4-wheel drive will come into play. Others may have a better explanation, but that's it in a nutshell.
Freshman User
Joined: Jul 2005
Posts: 29
Likes: 0
You got it 01fmlyexpy. When the rear wheel sensors pick up rear wheel spin, the t-case locks up via an electric solenoid/motor and engages the front axle. There are no locking hubs. In simple terms, the set up looks like a front wheel drive car with CV boots, diff, etc. The front drive shaft is always turning ready for action. Welcome aboard azshane1!
Logistics Pro
Joined: Oct 2000
Posts: 3,960
Likes: 5
From: All over Texas
Transfer Case — Automatic Four-Wheel Drive (A4WD)
Features and Operation
The automatic four-wheel drive (A4WD) transfer case uses an electronic shift 4x4 system that allows the operator to choose between three different 4x4 modes. The operator can switch between A4WD and 4WD HIGH modes at any speed. However, to engage or disengage LOW Range, the GEM requires that the vehicle speed is less than 5 km/h (3 mph), the brake is applied, and the transmission is in NEUTRAL.
In A4WD, the generic electronic module (GEM) varies the torque split between front and rear drivelines by controlling the transfer case clutch. Under most conditions, the GEM activates the transfer case clutch at a minimum duty cycle (percentage of time the clutch is turned on) which allows for a slight speed difference between the front and rear driveshafts which normally occurs when negotiating a corner on dry pavement. When the rear wheels are overpowered, the GEM detects this slip condition, and the duty cycle to the transfer case clutch is increased until the speed difference between driveshafts is reduced. In this manner, the GEM can redirect engine torque to the front wheels when the rear wheels lose traction yet still allow operation in the A4WD mode on dry pavement.
When the ABS system is active, the GEM will default to a minimum duty cycle for the transfer case clutch.
Feature Inputs:
l Shift range selector switch.
l Front and rear output shaft speed sensors (Hall effect sensor output: 11.86 Hz/km/h).
l ABS active input (battery voltage when ABS is active, grounded when inactive).
l Contact plate position inputs A, B, C, D grounded when closed, open circuit when open.
Feature Outputs:
l Solid state clutch relay (pulse width modulated signal: grounded when relay is on, battery potential when relay is off).
Shifting Between A4WD and 4WD HIGH
The operator can switch between A4WD and 4WD HIGH mode at any speed.
Shifting Into/Out of LOW RANGE
When shifting into or out of LOW RANGE, the GEM requires that the vehicle speed is less than 5 km/h (3 mph), the brake is applied, and the transmission is in NEUTRAL.
Features and Operation
The automatic four-wheel drive (A4WD) transfer case uses an electronic shift 4x4 system that allows the operator to choose between three different 4x4 modes. The operator can switch between A4WD and 4WD HIGH modes at any speed. However, to engage or disengage LOW Range, the GEM requires that the vehicle speed is less than 5 km/h (3 mph), the brake is applied, and the transmission is in NEUTRAL.
In A4WD, the generic electronic module (GEM) varies the torque split between front and rear drivelines by controlling the transfer case clutch. Under most conditions, the GEM activates the transfer case clutch at a minimum duty cycle (percentage of time the clutch is turned on) which allows for a slight speed difference between the front and rear driveshafts which normally occurs when negotiating a corner on dry pavement. When the rear wheels are overpowered, the GEM detects this slip condition, and the duty cycle to the transfer case clutch is increased until the speed difference between driveshafts is reduced. In this manner, the GEM can redirect engine torque to the front wheels when the rear wheels lose traction yet still allow operation in the A4WD mode on dry pavement.
When the ABS system is active, the GEM will default to a minimum duty cycle for the transfer case clutch.
Feature Inputs:
l Shift range selector switch.
l Front and rear output shaft speed sensors (Hall effect sensor output: 11.86 Hz/km/h).
l ABS active input (battery voltage when ABS is active, grounded when inactive).
l Contact plate position inputs A, B, C, D grounded when closed, open circuit when open.
Feature Outputs:
l Solid state clutch relay (pulse width modulated signal: grounded when relay is on, battery potential when relay is off).
Shifting Between A4WD and 4WD HIGH
The operator can switch between A4WD and 4WD HIGH mode at any speed.
Shifting Into/Out of LOW RANGE
When shifting into or out of LOW RANGE, the GEM requires that the vehicle speed is less than 5 km/h (3 mph), the brake is applied, and the transmission is in NEUTRAL.
