Havn't messed with the cooler on the IDI but the one on my IDI looks exactly like my powerstroke.
It's on the drives side under the exhaust manifold. It runs from the front of the block to the back and the oil filter screws into it's rear housing.
On the 7.3 PSD in the Superduty, to remove it you take the bolts out of the front and rear housings and try to get it out as an assembly. once out it should be 3 pieces when you take it apart, the front housing, the rear housing and the oil cooler itself which is the tube.
There is a gasket for the front housing, a gasket for the rear housing and 2 O-rings on each end of the tube.
Can't help you more than that on the IDI so hopefully somebody will chime in and correct this if there is anything special about the IDI oil cooler I don't know about.
Here's a pic showing the placement on my 7.3 powerstroke when I had it out. It's in the same place on my IDI and looks exactly the same.
Good luck
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