Can't find diff drain plug
 

I have my 1999 Carrera 2 with Tip on Jack stands to drain and refill differential. I can see the 8mm fill plug on the drivers side near the axle shaft on the vertical surface, but I can't see the 14mm drain plug that is supposed to be at the bottom of the ribbed bulge below on a horizontal surface. dslamitz on youtube shows it on his '99, but the drain plug is not there on mine. I am told my engine was replaced with a used engine. Is it possible "98" engines, ie. very early 99's had no drain plug? I need better pictures or diagrams of 98 and 99 differentials to figure this out. Any help would be very much appreciated. Thx