98 GMC Jimmy tranny wirring sound

Hello, My GMC Jimmy VIN code W 8cyl VORTEX engine w/ auto tranny 4WD's tranny is not working properly. At first reverse would studder, like clutch slip, then in drive it will shift into drive and move but will not shift until 3000 RPM and it kind of sticks until it will shift hard. Neutral, reverse, and park makes a wirring sound from the tranny. I am currently chaning the oil which hasen't been changed since the tranny rebuild. The tranny was rebuilt at 120k miles and the truck has 207k miles now. I read on another topic that it just may be the filter. Any ideas?