Playback of recorded material is "garbled"

Playback of recorded material is "garbled"

Is that garbled sound, that you are discribing, like if you sing a not and lightly punch yourself in the chest? Because that’s the problem that I have with my deck. I ordered Awesome Mix tapes from the movie Guardians of the Galaxy (meaning they are new) and when I play them on my walkman they sound fine, but when I play them on my Sony TC-K370 the sound is as I described... Is the problem in the belts? Or the little wheel?