hi every one. i am new to the forum and have a tech. question. i have a 03 cavi thats auto and it has about 70,000 miles on it. the air is on or even the heat and my transmission feels like it will drop when i am starting from a red light or stop sign. only in 1st to second this does it. also with the transmission, when i am in third gear it feels like it is slipping from second to third, like it wont get into gear and it revs then catches the gear. but it does not clunk....................what is the problem? the clunk only happens when the air or heat is on ppppppllllleeeeeeeeezzzzzzz help thank you