Volvo: 96 850Trans issue, forward gears, shift lock

Question
Hello Sir, 96 850 turbo, 1st: in order to get the Shifter out of P to drive you have to depress the shift lock button
2nd: if i want to Reverse, it will shift into reverse, you have to let it roll on its own ( slight uphill, even a driveway it wont back up) you can press the pedal and wont move, vibrates violently untill you switch back into P or dirve. it drives fine and shifts fine going foward. Any suggestions? i would hightly appreciate this.

Answer
Aspet,
The shift lock will need some inspection. The weak point in the system is the micro switch on the shifter. If the car will not move in reverse, but does in the forward gears the trans is gone out. If the car is clean and worth the $2000.00 to repair it, have it done.