A4wd differs from AWD in function.
AWD generally refers to All Wheel Drive which is designed to deliver power to all 4 wheels at all times. These generally have some sort of differential between the front and rear axles to allow for difference in speed between them during turns and normal driving. Total of 3 differentials, front, rear, center.
A4wd is Automatic 4 wheel drive on demand. These run in 2wd mode unless slip is detected at the rear wheels then it engages 4wd only on demand via a clutch in the transfer case. This system is not designed to run in 4wd mode on dry pavement or high traction conditions. There is no differential between the front and rear axles so when the transfer case clutch is engaged the front and rear axles must spin at the same rate. The drivetrain will bind up noticable if 4wd is engaged while turning on pavement due to the difference in distance traveled between the front and rear wheels.
These two systems differ dramatically in design and function.
In short.... the first generation expeditions are running in 2wd unless the gem module detects slip while in A4wd.
The brown wire mod or removing the fuse simply keeps the gem from engaging the clutch when/if wheel slip is detected.
AWD generally refers to All Wheel Drive which is designed to deliver power to all 4 wheels at all times. These generally have some sort of differential between the front and rear axles to allow for difference in speed between them during turns and normal driving. Total of 3 differentials, front, rear, center.
A4wd is Automatic 4 wheel drive on demand. These run in 2wd mode unless slip is detected at the rear wheels then it engages 4wd only on demand via a clutch in the transfer case. This system is not designed to run in 4wd mode on dry pavement or high traction conditions. There is no differential between the front and rear axles so when the transfer case clutch is engaged the front and rear axles must spin at the same rate. The drivetrain will bind up noticable if 4wd is engaged while turning on pavement due to the difference in distance traveled between the front and rear wheels.
These two systems differ dramatically in design and function.
In short.... the first generation expeditions are running in 2wd unless the gem module detects slip while in A4wd.
The brown wire mod or removing the fuse simply keeps the gem from engaging the clutch when/if wheel slip is detected.
Last edited:
