This specification provides a list of test methods and acceptance criteria for determining the performance acceptability of gear lubricants used in nonsynchronized heavy duty manual transmission (MT-1). The test methods listed here shall be able to examine the following properties of the gear lubricants: viscosity increase; pentane insolubles; toluene insolubles; carbon/varnish rating; sludge rating; hardness and volume change, and elongation of polyacrylate and fluoroelastomer; falling load stage; and foam tendency.