Q: Why won't my car move when I put it in drive or reverse but when I stick it back in park all it does is grind

I’ll bet you have a broken CV joint. The CV joint is the joint in the axle shafts that allows the front wheels to be under power when they are steering. When the joint fails, the axle is allowed to freewheel without turning the front wheel so the car doesn’t move. It also means that when you step on the brake to put the car in park, it doesn’t stop the axle from turning so it’s just like trying to put the cat in park while it is moving. To get the car in park, just shut off the engine. Then you can contact Your Mechanic to have a technician come out to your home or office to inspect your car right there on the spot and let you know exactly what it is going to take to fix it.