Fluid is clear red as it should be and is at proper level. I dont think it's the trans. It's more like the car is being held back. Identical to if I was to hold the brake and gas at the same time

Hello I recently purchased a a 2006 volvo xc90 with the 2.5t engine. When I'm stopped and press the gas it hesitates to accelerate. The rpms go up to idk at least 2 Grand then it goes. If I'm on a flat surface, put it in drive and let off the brake it doesn't move. Once it gets going it drives and s...