Well, if we want to get "technical", there is no "sending unit". As per the factory parts book:
11 53020827 1 EK0, EV0 PUMP, Engine Oil
17 04868672AA 1 EK0, EV0 SWITCH, Oil Pressure
I don't know if its a regional thing, as I'm from NJ and we've always generically called anything that sends a signal to a gauge or the computer as a sending unit. I've never heard of a pump itself being called a sending unit. Hopefully the OP got what he needed out of this.
To the OP, these will help:
Factory service manual, click on link, then click on green download button off to right
Factory parts manual
2003 Ram 1500 QC Hemi Lonestar "Big Red" (Mods list in profile)
2006 Charger R/T "Little Red"
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