95 mazda mpv wont reverse

hi today i purchased a 95 mazda mpv v6 with 109k miles. i test drove it, went over everything including checking the trans fluid (which smelled fine and was the correct color) and all was well. i was impressed! with all the excitement, the one thing i didnt check was the reverse... i didnt have a situation where i needed to go into reverse during the test drive. when i got the car home, i had to use reverse and this was when i made the discovery. every other gear works perfectly. after a few tries, it went into reverse but first it made a growling or high pitched whining sound... then it engaged into reverse. any ideas on what the problem is? could it be an adjustment needed to be made in there somewhere? any help will be greatly appreciated. dude