CJ750 toolbox Secondary gearbox drain by Ross Kowalski
I just did the modification to the transmission on the red bike allowing all the transmission fluid/30W oil/water to be removed. As I leave the bike outside all year, I get water in the transmission and if I don't drain the little pocket below the shift plate on the hand shifter side of the transmission, there is always water in the fluid when I drain it. An extra drain hole allows this little area to also be drained of water or whatever.
The right side of the transmission showing the shift plate and the little protrusion below it where the water collects.
Start to drill a pilot hole in the back of the little protrusion with an 1/16 inch pilot bit. This area should allow for clearance with the shift plate. Don't drill through.
Place a cup under the hole as oil will flow out when the hole is made.
Oil will flow out, which is good because you would rather flush chips out of the casting. Notice that my oil (30W non detergent oil) is frothy which is why I did this mod in the first place.
Drill a clearance hole for the tap that you are going to use. I think it was 11/64.
Tap the hole to the hole. I think I did a 12-24. Again, the oil flowing out is a good way to keep the chips out so let it go.
I put a little washer on the screw to protect the block. It probably only needs to be 3/8 but I didn't feel like cutting it down.
Screw the plug into the tapped hole and confirm that the hand shifter can do all four gears.
The completed drain is fairly unobtrusive and with luck you will never need to drain water out of your case.