Schwimmwagen's gearbox

[Capt Gottlieb]

At last I have found a very good schema, a simple drawing from Schwimmwagen's gearbox. There are some explanations in German, English, French and Italian. The Schwimmwagen used basic mecanic project of VW Beetle Sedan, however it was a militar vehicle, rude, strong, stout and amphibious. The transmission was similar (not quite equal) with Beetle sedan but with some improviments, mainly in gearbox. So it was possible ride around using 4x2, 4x4 (4WD) and cross country gear. The gearbox was quite unsynchronized, perhaps a bit awkward to drive. 4WD and cross country gear were possible only with first speed. Perhaps this gearbox has seemed TOP SECRET but now is clear up.

During the WWII germans made 14000 Schwimmwagen, a military version of VW sedan, amphibious and with four-wheel drive (4WD). But in May 1945 only a few vehicles have survived.

_________________
Simplicity is the ultimate sophistication.
Exaggeration is a disguised way of lying.

[Capt Gottlieb]

We can consider thar Schwimmwagen had a gearbox with five speeds (1st, 2nd, 3rd, 4th and the cross-country). Four wheel drive (4WD) was only possible with 1st speed (the system did not accept the others ones). And the cross-country speed was only possible if the gear lever were in 1st speed position and with 4WD.

All Schwimmwagen were four wheel drive only on first gear (and reverse gears with some models) and had ZF self-locking differentials on both front and rear axles. Just like the Kübelwagen, the Schwimmwagen had portal gear rear hubs that gave better ground clearance, while at the same time reducing drive-line torque stresses with their gear reduction at the wheels.

_________________
Simplicity is the ultimate sophistication.
Exaggeration is a disguised way of lying.

[finster]

I'm pretty sure it was only the rear wheels that had portal axles (reduction gears) not the fronts.

[Capt Gottlieb]

[Capt Gottlieb]

Just like the Kübelwagen, the Schwimmwagen had portal-axles gear rear hubs that gave better (higher) ground clearance, while at the same time reducing drive-line torque stresses with their gear reduction at the wheels. But the portal-axles in the rear is a reduction and at first glance it seems that the rotation of the front and rear wheels would be different, which would be a catastrophic mistake. The solution found by germans was to change the number of pinion teeth, but the rings had always 39 tooth. The front pinion had 6 tooth and the back pinion had 12 tooth. The portal axle has 13/26 tooth and reduces by 1:2. And so the final rotation of the front and rear wheels with 4x4 traction are the same.

From the drawing (scheme) posted below and from what all indicates those dimensions in the gears are the numbers of gears tooth. So the front differential has 39/6 tooth but the rear differential is twice faster, 39/12. The portal-axles "reduce" twice (13/26 or 1:2). So the rear differential is in the same ratio as the front.

Curiosity: In the past VW made Kombi (BUS) in BRAZIL with VW 1200 engine, gearbox (4 speed) and rear portal-axles.

_________________
Simplicity is the ultimate sophistication.
Exaggeration is a disguised way of lying.

[geneL3c]

German made VW Buses, Typ II, had reduction boxes ( portal axles ) from 1950 until 1967. I'm sure Brazilian produced Buses likely continued well past 1967.

[Capt Gottlieb]