Given more frequent engine shutdowns to save fuel, rising soot levels due to emission requirements, and the demands of the customer for extended oil drains, we must still ensure prompt oil pumpability for both fresh and used oils. To develop oils which meet these requirements, we used two Cummins M-11 tests. The first assessed the fresh oil's pumpability times to the oil gallery, turbocharger, cam roller follower and rocker shaft at -15°C (+5°F). In the second, we used the Cummins M-11 test from the API CH-4 category to generate 9% soot levels in end of test oils. These used oils were then evaluated in MRV TP-1 and Scanning Brookfield for low temperature pumpability.As an adjunct to the above study, we compared an SAE 5W-40 synthetic to SAE 15W-40 oils in regard to wear and fuel economy. These field tests were conducted in line-haul trucks operating in North America with Detroit Diesel Series 60 and Caterpillar 3406E engines.