2000 Isuzu NPR Box truck

I’m selling my Isuzu NPR due to a bad transmission. It will only engage in reverse. It was working fine and it had a small leak in the line. We replaced the line that was leaking and added tranny oil. Now it won’t engage in drive. I’ve decided to sell as is and not invest anymore in it. I recently installed new batteries, replaced Air filter, oil filter & fresh oil ,and fuel filter. Purchased a new brake booster from the Isuzu Dealer and got it installed. My loss is your gain. I’m open to offers but please don’t low ball me. I know what the engine alone is worth. It’ll have to be towed unless you’re mechanically inclined and you might know what’s causing it to not engage in drive. This is strictly a cash deal.