The Helms can be a nightmare trying to chase something through the manual. Those that have them will know what I mean. It's chiefly a diagnostic and repair hint book for the Techs, and not a how we did it, part numbers, and where it goes book. That said, many, many of the illustrations are Monaro specific and give hints to possibly untapped capabilities in the GTO version. One such is the Transmission 'Mode' swith for the A4's that is present on the Monaro, but the switch and location for it are missing in the GTO, just as the underhood lamp is, but they're both in the Helms. I started chasing this a while ago, and put it aside when my eyes crossed. I am going to post what I have found in dollops as I confirm the books with a look in the car (some disassembly required)... Here is the starter.