I see you have already taken the appropriate action!
Oil will run to the lowest point when sitting, and the lowest ,rearmost point when moving forward. Visually check everywhere on the engine. Usual suspects are valve covers, intake to block and head joints, hoses, and pipe plugs. Worst case scenario is rear main crank seal. Pull the engine/tranny type repair. But try every thing else first ! Best procedure is to wash down engine to remove exsisting
oil & grime, but you must be very thorough to avoid false readings, and get a dye ck kit.