4x4 Explained

Introduction to All Wheel Drive systems - By Eliot Lim

Definitions

It is important to get the definitions down first, since for any four wheeled vehicle, all wheel drive and four wheel drive literally mean the same thing. Generally speaking "all wheel drive" implies permanently engaged or automatically engaging four wheel drive and "four wheel drive" implies manually engaging, part time four wheel drive. The auto industry usually abide by these definitions but not in all cases. The now departed "all wheel drive" Ford Tempo and Subaru Justy were really part time manually engaging systems, like the older Subaru GLs. The term on demand four wheel drive is quite ambiguous. It can either mean that it is a part time manually engaging system or a part time automatically engaging system!

The automotive media shares a lot of the responsibility for the confusion. Factual errors are common, so is the careless use of the various terms interchangebly.

For this article I shall be using the terms loosely and will be more specific where necessary.

NEXT SECTION