Plugs are extensively used in earthmoving machinery for maintenance purposes. Loss of these plugs, stripping of the threads, or difficulty in finding the right tool, can result in serious damage and/or increased down time.
SAE J371A-1978 history
2016SAE J371-2016 Drain@ Fill and Level Plugs for Off-Road@ Self-Propelled Work Machines
2010SAE J371-2010 Drain, Fill, and Level Plugs for Off-Road, Self-Propelled Work Machines
2006SAE J371-2006 Drain, Fill, and Level Plugs for Off-Road, Self-Propelled work machines
1993SAE J371-1993 DRAIN, FILL, AND LEVEL PLUGS FOR OFF-ROAD, SELF-PROPELLED WORK MACHINES
1985SAE J371-1985 Drain@ Fill and Level Plugs for Off-Road@ Self-Propelled Work Machines
1978SAE J371A-1978 DRAIN, FILL, AND LEVEL PLUGS FOR EARTHMOVING MACHINERY