93 Achieva 3300 - No Reverse -

Just bought this 93 Achieva with the 3300 v6 in it. Car has 230 000kms on it, all highway. The car drives awesome in drive, pulls hard and shifts smooth. But when you put it in reverse it still goes forward. Guy i bought i off said that the clutch packs are both going the right way and the one won't go backwards.

Any ideas on the problem? Do I need a new tranny (haven't found one yet), or is it something else?

Thans,
Seb.