AT-28 AUTOMATIC TRANSMISSION — Road Test 4. "R" RANGE TEST Shift into "R" range and, while starting at full throttle, check for slipping. [DIAGRAM: Full Throttle Valve Opening gauge indicator marked 'R' and 'PRNDL', plus illustration showing slippage] 5. "P" RANGE TEST Stop the vehicle on a gradient (more than 9 %) and after shifting into "P" range, release the parking brake. Then check to see that the parking lock pawl is functioning to prevent the vehicle from moving. [DIAGRAM: Parking Lock Pawl Acting indicator marked 'P' and 'PRNDL', plus illustrations showing vehicle on gradient]