Was replacing the t-stat and water pump on my truck and noticed that the freeze plug right behind the turbo was leaking. Went to several different parts houses only to find that the one's they list if they listed anything were all too small, also when they measured it out nobody seemed to stock the proper size. Finally went to cummins to find the right one. For everyone's info. the cummins part # is 3922072.... at least for my 97. Also the freeze plug installers I have do not have a cup big enough so it's a real pain in the neck to get it installed correctly, I ended up taking the turbo and water pipe to the front of the trans. heat exchanger both loose so that I could get a straight shot at the bloody thing. Just thought I'd throw the part # out there in case anyone has the same issue.

 

At least it wasn't the one at the back of the engine.
Talk about a pain to replace.