2005 GP base with 140k miles. Say I'm going through a parking lot or something, starting from a stop sign going 5-20 mph. When it shifts to second it whistles through it; just a simple whistle completely through the shift. Only 1st to 2nd and only going slow, highest it happens is probably 15-25. Say I'm at a red light on a highway and trying to reach 45-50 it doesn't do it. Have 2 gallons of fluid and a new filter I plan on changing out and when I am under there I'd like to know where to look for a possible cause.