When you do a pan drop on a 4L60E transmission, you will typically need to refill it with about 5 to 7 quarts of transmission fluid. It's always good practice to start with 5 quarts, then check the fluid level while the engine is running and add more as needed to reach the proper level on the dipstick. Be sure to use the recommended type of transmission fluid for the 4L60E transmission to ensure optimal performance.