There is another
thread that would have told you everything you need to know about this.
We have the same problem. It seems that the spring on the shifter must be looser this year than previous years because it hasn't been a problem for us before and this year it is happening to both of our drill motors.
Dave lavery's White Paper on disassembling the drill motors will help you to find out how to get to the spring, and I guess I'll just quote Ken Leung from the above mentioned
thread when he tells us what the problem is and how to fix it. Ken says:
"The way the spring work is the more you turn on the dial toward "drill", the harder it press on the spring, and the harder the spring press onto the little metal balls under it.
So, one good way to lock the clutch in gear is to take the spring out, and replace with a solid ring the length of spring when compressed the most. Then the metal balls will be flush with the holes, and grab onto the ring gear with little notch completely and prevent it from slipping.
The other way is to take away the dial completely, and the metal balls as well, and tap the hole, and put set screws in instead."
Thanks to all of these helpful folks for the information, and thank you for searching for "Drill Motor Slippage" before you post a new thread next time.