Not shown in V4 parts book. No series is very close to tool for Saab 99, though these have an extra no. Not shown in Saab 99 W/S manual upto 1974. Are you able to post a photo?
Interesting! All the V4 gearboxes I've come across have a square hole in the drain plug that is a perfect fit for a 3/8" socket drive- except for one! The drain plug in that one was a different diameter and had a circular hole with a bar across it! That box is now either in the white 95 I used to have, or the spare in my garage! I'm on holiday in France at present, so can't check, but that tool looks like the one needed for that box!
I made my own by sawing slots in an old socket....!
-- Pete "Duct tape is like the Force: It has a light side and a dark side, and it binds the Universe together!"
I must have had too much vino the other night!! Just checked w/s manual and it is there. I have had one v4 gearbox with this type of plug and took ages to get it out. My other gearboxes have had the square drive as it is easier to get out.
My 1969 V4 had that type of drain plug and I have the tool somewhere. The one on Sonett is a square hole though, so I expect the change was early '70's