Listies

While dismantling an 86 van and removing it's radiator there was a second cooling unit directly behind the radiator, it had two lines attached to the bottom of it,  they seem to be oil lines or perhaps even transmission oil  lines. In looking through both Haynes and Bentley I cannot find any evidence of this second cooling radiator.  Someone help me out what is this second radiator type cooling device ?

regards.
clarence
1990 multivan
pinehurst, nc