During the first Gulf War, the vehicles suffered from sand ingress, which resulted in a total failure of the engine plant. A modification was quickly introduced to raise the air intake to avoid the sand ingress. During 2002 the fleet underwent a major midlife upgrade and refurbishment. This included the introduction of an anti-lock braking system (ABS). The MMLC had two trailer types, (known as "king" and "queen" trailers) specifically designed to carry the same load pallet which was transferred from the main vehicle. The queen trailer was supplied by Reynolds Boughton but the king trailer was indeed supplied by King Trailers who have since 1962 been the UK's biggest manufacturer of trailers for specialist loads. The Leyland DAF MMLC vehicles were mainly issued to the Royal Corps of Transport (RCT), later to become Royal Logistic Corps (RLC), however a number of these vehicles were provided to other units along with the RAF Regiment.