Here's a manual for the W58 Transmission. Hermann suggests a W58
because of the gear ratios in fifth, but there's actually something
to be said for the W55 ratios in lower gears. You can't tell the
difference between a W55 and a W58 without checking the gear ratio,
so in the end I decided to just take either. Hermann has a
guide for how to check for a W58 transmission
Thanks to the Supra library at cygnusx1.net for the manual.