Grinder Treads is Soviet Line 2 Top Secret Protocol in Command & Conquer: Red Alert 3. This enhances all vehicles that are able to crush enemies. Every time an enemy is crushed, the vehicle will recover any lost armor. Higher tier vehicles that are crushed will grant more armor recovery. Higher threat levels will also increase the effect.
If a tank (e.g Hammer Tank ) squishes infantry, a special sound effect will play and a wrench icon will appear above the unit's health bar (if the machine was damaged). The amount of health reclaimed depends on the value of the unit. It also multiplies the effect by a current amount as the Threat Meter grows.