transmission on 240d

[minni71317]

i just bought a 1982 240d for $650 engine runs good rides nice at high speeds runs cool, when I test drove the car the trans shifted very smoothly, now its kinda goofy. you have to really rev it up to high speeds before it will shift and when you park it on a moderate incline it jumps out of gear when you put it in park so i have to use the e brake, i bought it for a winter car the car is pretty clean but i don't really want to put alot of money into a new transmission, can someoe please tell me if there is a simple fix or if my trans is toast