Fine tooth gear pros

[Casting Timmy]

I know the factory did fine tooth since they are faster and cheaper to cut, but sometimes you hear them called low loss gears.

Do the fine tooth gears besides being quieter also generate less heat as well?

I also find it very interesting that on beetles people hate the idea of fine tooth gears, but people talk about a six rib but have no idea of the fine tooth gears in it. I know they are wider, but that box was also designed for the heavier bus and a T4 motor.

[Pablo2]

VW went to low loss gears because they're quiet and efficient, not because they're easier to make. Since the overlap ratio is much higher with these (more teeth in engagement at any given moment), the smaller teeth have adequate strength. The real problem is mainshaft ball bearing failure, which of course causes tooth misalignment in 3rd and especially 4th gear. These fine toothed gears cannot tolerate sloppy engagement/excessive clearance.

As the weight of later model Vanagons increased, VW eventually went to a much stronger version of low loss gears:
http://images.thesamba.com/vw/gallery/pix/1400261.jpg

[Casting Timmy]

What'd they do to make the gears stronger? Are they cut deeper or wider gears than even the 091's?

[Pablo2]

Did you look at the link?

[Casting Timmy]

It looks like they did a medium cut on the second gear set. When did they start doing that and do they interchange with 091 gears?

It seems like some of the 091 gears are drying up and some are common.

[Pablo2]

I think all Waterboxer 3rds & 4ths have the larger teeth. From the photo, the difference in width of 4th fixed gears can be seen (which could be ground off the waterboxer gear). Keep in mind the difference in bore diameter of 091 and 091/1 idler gears (made up with different bearing).