It's actually a pawl, but that's unlikely to be the problem. Most common on your car is a bad park cable or something wrong with the shifter box. When you slide the park lever down, the cable should move and engage the parking pawl inside the extension housing. You can't see it work from the outside without taking the access cover off but you can look under the dash and see if the cable is moving on that end. If that's not the problem, remove the cable from the transmission end and pull the little cover off. You should be able to manually move the linkage for the parking pawl and engage it. The driveshaft will lock in place when the pawl is engaged. On the odd chance that the pawl or related part(s) are broken, you'd have to pull the extension housing off to replace them.