Lloyd "Truck" Garrick is an African American narcotics officer in Sergeant Ellis Carver's squad in the Western District of the Baltimore Police Department, often partnered with fellow squad members Herc, Lambert and Colicchio.
Garrick was part of the operation that resulted in the shooting of Officer Dozerman. Along with the rest of the squad Garrick was involved in policing drug tolerant zones set up by his district commander Howard "Bunny" Colvin without the knowledge of his superiors. He was with Herc when he phoned the paper to report Colvin's actions and again when he met with a reporter.
In season 4, Truck appeared briefly at a useless lesson for Western police on counter-terrorism and once assisting Herc and Carver.
In Season 5, Truck appears with the Western District officers who are frustrated by the lack of overtime pay due to city cutbacks. During Detective Jimmy McNulty's homeless killer case, McNulty has Western District Sergeant Ellis Carver detail officers to track Marlo Stanfield's crew including officers Brown, Dozerman, and Truck.