3975986 Cummins Transmission Cooler 3" X 9" OAL bundle Diameter Oil Cooler CuNi. 3975986 and 3975986CN are the same part, both with a Copper Nickel bundle.
Core length = 6", overall length = 9.5" (tail to tail)
This cooler has 1.3/4" water fittings.
This is a non-OEM, aftermarket part MEC 3975986