I don't know on the drain plug, but i do recall somewhere, a person having posted an image of what appeared to be a drain plug, located in/on the housing assembly of the PTU.
I saw the image, & it did appear factory.
Non PP SHO's, for 2013+ do not have the auxiliary coolers.
I.E. Auxiliary Oil, Trans, & I stand corrected......
I misspoke...... the auxiliary cooler goes to the rear diff IIRC, not the PTU as I previously advised.
I'm at work at the moment & don't have the ability to double check schematics.
Perhaps someone else can chime in, in the interim.
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