09-20-2021, 04:06 AM
Yes, 3/8 square drive plug . I checked parts manual , your engine likely came with that 1/2 npt plug . Detroit used several drain plug sizes for various engine types.
Glad you worked it out !
Glad you worked it out !
1986 #89
VIN 007
Detroit 8V92 TA 475 HP
Allison four speed
Chris and Sharon Hand