I got this from crown thread on toymods
My mate has it in his '64 rs46 Wagon i've got a '66 wagon with no overdrive
Put some photos up on there if you want
There is a lot of good information in that thread its a good read
http://www.toymods.org.au/forums/showthread.php?t=481&page=33&p=725302&highlight=overdrive#post725302
Had one of these in my first crown.
1. with overdrive button in all the time freewheels--got great fuel economy once I realised and took foot off accelerator when on long downhill runs etc.
2. with overdrive button in only needed to use clutch starting off in first, any other change take foot off accelerator briefly change gear then put foot down again (no need to put clutch in).
3. with overdrive button in, hit accelerator hard and it will kickdown as autos do, used to kick down and hold second until past 60 mph.
overall one of the most fun setups I had driven
Greg