Hey guys. My 2004 3.8L Impala has been acting really weird lately. Today, I took not out for a drive and drive maybe 30 miles and the transmission started slipping out of gear. After I parked, disconnected the battery for about 45 minutes, tried hoping in and here is what happens. My car shifts fine into Reverse, but when I switch from Reverse to Drive, nothing happens, almost as if I shifted from Reverse to Neutral. My car will not accelerate unless I shift into a low gear such as 1st, then I can shift into 2nd and 3rd but if I shift into drive from Reverse, my car goes nowhere. Any suggestions? Low ATF fluid possibly or a clogged filter? Any help would greatly be appreciated!