2002 ss shifting hard

on my way to work today my trany was shifting fast and hiting the next gear hard. also the speedometer will read zero until i've accelerated over fifty five. any ides what the problem is?

Many of the 4 spd. electronic transmissions have had trouble with the electric selenoids. Especially 1st to 2nd. Take you car to Autozone and they will check the OBD II free. This will give you an indication what is wrong. Your Chevy dealer can do a more indepth check for $$$. If it's the 1870 code, most good transmission shops know what to do. Best of luck.