Hi,I recently purchased a 2003 Chevy 3500 duramax 6 spd.180,000 miles.. The clutch feels really soft and it stays down close to the floor until it has been pressed several times, then it seems to do better. Also the transmission does not always down shift, sometimes i have to turn the key off and put it in gear then start it back up. could this be a missing/broken spring and maybe just need to replace the tranny fluid and filter? Please help as i am definately not a mechanic..Thanks in advance!