my truck is a 2002 avalanche with the 4l60e and it started missing shifts or sometimes it wouldnt shift at all. I was told to replace the filter and it helped a bit but it still wont shift right it will rev up real high and wont shift until i let go of the gas. Im thinking it might be the shift solenoids. Or is the transmission crapping out? Any input or suggestions as to what might be the problem is highly appreciated.