I have an 07 silverado reg cab with the 4.3 L and the 4 speed transmission. it has 71000 miles. yesterday i was driving just normally up a hill by my house. when it hit 2nd gear it just went BOOOM and rocked the whole truck. Drive and 3rd gear dont work but 1st and 2nd and reverse still work. I took it to the shop and they say i need a new transmission..... why did this happen so early? im a big chevy fan but this should not have happened.