Hi, I was trying to figure out how the transgo kit works and what purpose the drilling has. I think there are three holes in the c2 apply piston and two in the valve body that need to be drilled. I haven't been able to locate any detailed description of operation. Thanks for any info.http://dieselplace.com/forum/smileys/Big%20Smile.gif

I don't know about on the Allison, but on Ford's 4R70W, when one does the "J-Mod" (A shift kit designed by one of the people who designed the transmission), opening up the holes allows fluid to fill the accumulators faster, thus alowing the shifts to engage faster. I think the transgo kit for the 4R70W is basically the same, and I would imagine the concept would be the same for the Allison.