Straight-mounted engine - All-wheel Drive
In the course of history, the standard drive train (straight mounted front engine, rear-wheel drive) was the first to be developed into an all-wheel drive. At that time, it was still the most widespread combination. A four-
speed gearbox was still considered by some to be a luxury. Thus, a simple method was created, to add a front-wheel drive, to the rear-wheel drive. Because this was only necessary under off-road conditions, it wasn't
much of a problem to disengage it on roads where the grip was good.
At the exit of the four-speed gearbox, a gear- or chain driven transfer case (see figure) is flanged onto the exit. The differential shaft is shortened accordingly. This drive is engageable when the sliding sleeve is moved
the left. From the lower exit, it leads, on the left, to the front (rigid) axle. This receives the same final drive as the rear axle, indeed with the crown-wheel on the the other side. If required differential locking could also be
One problem still arose. Mostly the traction power of the engine was not sufficient to pull the vehicle out when it was bogged in. This, even moreso, the better the traction of all four wheels was. For this reason, the
transfer case was increased to a two-speed gearbox. Please take note that both wheels on the main shaft were free-wheels. This resulted in:
Sliding sleeve to the left - off-road ratio-reduction (all-wheel drive)
Sliding sleeve in the center position - rear-wheel drive only
Sliding sleeve to the right - normal gear ratio (all-wheel drive).
To reduce the fuel consumption of an all-wheel drive vehicle and to reduce the strain on the additional gearbox, the front axles were fitted with a 'lock/unlock' position. Thus, one could disengage the wheels from the
axle. However, make very sure that you don't forget to put the drive wheels in the 'lock' position before going into difficult terrain ...
Later, these were replaced by front axle drive shafts with freewheel system. 02/18