transmission shifting/banging hard only after 20 minutes of driving..why? on 2004 Chevrolet Monte Carlo

transmission shifts hard after 20 minutes of driving the car especially if im at a red light or stop sign then i hit the gas to go it bangs into first and second gear its awful

by in Malden, MA on April 06, 2013
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1 answer
ANSWER by , April 06, 2013
get to tranny shop for diagnostic. tranny tech. will advise.