You also can use a piece of wire to hold the shft into the tranny case. This will lock it into second. Right now I have a wire wrapped around a screw on the tranny case connected to the shaft to hold it in. I am going to upgrade to the gmaxx conversion soon.
Either way - you cant go wrong. I've been using the wire and screw method for a long while now - it worked fine - now i have the single speed conversion - so that ends the screw wire combo...
Yes, I stock these. The conversion includes the coupler, front case cover, screws and instructions. This is by far the best way to do it. The coupler provides a positive engagement (no slop like the stock tranny), which is better for a couple reasons. Primarily, it reduces the stress associated with the play (stress on internal gears as well as all drivetrain components), especially with high powered systems.