TSB: Some 4WD equipped 2010 ? 2013 model year SR5 and Trail grade 4Runner vehicles may exhibit a clunk/thunk noise from the rear of the vehicle or a ?bump-from-behind? sensation just before a stop or when accelerating from a stop. Improvements have been implemented on the rear propeller shaft (driveshaft) to reduce this condition. Follow the Repair Procedure in this bulletin to improve this condition.
