Transmission

When I bought the Vanagon, the seller told me that the transmission needed work, it was making grinding noises and popped out of gear.

Now the weak points of these transmissions are the 4th and 5th synchronizer body that cracks and breaks, it gets stuck in gear and is hard or impossible to get out. Also the double roller pinion bearing, main shaft bearing and 5th gear needle bearing run too hot and eventually will fail, especially if a more powerful engine is installed.

To improve the internal oiling of the bearings you can install plastic drip trays that were developed for the South African Vanagon that had a 5 cyl Audi engine, but still these tranny's absorb a lot of heat from the engine and eventually fail.

On my transmission, the synchronizer body was broken, main bearing split and housing scored.To improve the lubrication, I have drilled an oil channel through the housing to the double roller pinion bearing, cut a radial groove outside around the bearing with 3 small holes to the center of the bearing. Now it will have filtered and cooled oil pumped through the bearing center.

Also I have drilled an oil channel into the main shaft to the needle bearing cages of the 4th and 5th gears, put a spray nozzle on the main shaft bearing and one on the pinion.
External oil pressure is supplied by an extra power steering pump, that pumps the oil through an oil filter and then through a cooler into the tranny.You can see all the external pressure lines on the pictures.I hope that this will keep the tranny together for a long time.

To bring the engine revs down a bit, I have installed different 4th and 5th gears, they have nice big teeth on them, the original gears have very fine teeth and are known to fail. The new ratio's are: 1.14 : 1 third gear and 0.77 : 1 for the fourth gear.