in the early eighties my 727 with a Street Trans Go shifted so hard it broke the end off the band and the servo piston almost went thru the bottom of the pan. I bought a new band and the trans guy said "drill a 1/8 hole in the piston, it'll bleed off some of the pressure." I did and it would slip from drive to reverse to drive almost like when it was stock, it shifted firm but not hard normal driving, but it would still chirp the tires under power. piston is still in there today.
