Range Rover sport-utility vehicles sold in the United States are being investigated by the National Highway Traffic Safety Administration (NHTSA) over complaints about faulty front differentials or driveshafts.

On its website, the NHTSA said: "Consumers are alleging failure of the front differential and/or the front driveshaft, resulting in a loss of propulsion and immobilisation of the vehicle."

The agency estimates that 33,000 vehicles from the 2002-2004 model years are affected.

The agency said it had received 38 complaints with 17 alleging that the failure occurred while driving at speeds over 40mph. 16 consumers said the vehicle needed to be towed for repair after the failures while eight complaned they had experienced two failures of the front differential and/or front driveshaft.

The NHTSA has opened what it calls a 'Preliminary Examination' of the problem.