When driving feels like its in first for a while and the rpms are high up to 3000 rpms then finally goes to second after getting up to speed a little faster then 25 mph. It was never like this before. I did notice slight leaking of the trans fluid so I checked the levels and it was low so I refilled to the proper level. That was a few days ago and its still at the right level so the leak must be very slow. What could this be??? Shift solenoid? Band? Is the shift solenoid still working right cause it eventually shifts buy slower? Please help!!!