What is the drill mod?
To sum it up, basically GM didn’t think things through all the way when selecting the hydraulic lines for your T56. The steel braided line that plugs into the master cylinder has a tiny, tiny hole in it, which causes unnecessary restriction. During a quick, high-rpm shift, fluid cannot get where it needs to go fast enough, so basically it will feel like you are shifting without a clutch. It may be difficult or impossible to shift into 2nd or 3rd, and you may have some problems with the pedal itself. When performing the drill mod, you remove the master cylinder, separate the line from the cylinder, and drill it out.
