I have a 2002 ranger edge, the tranny went out so I pulled one from a supposedly working truck with 110k on it (ecm got fried and they just didn’t want to replace it so it became a parts truck)

I installed it, changed the filter and fluid, old fluid was clean and had no metal in the pan at all, almost looked brand new. Went to drive the truck and it seems as though it doesn’t want to shift out of first gear, it revs up to about 3000 rpm and just stays there and doesn’t seem to shift. The OD OFF light is flashing and I’m going to pull the codes off of it tomorrow to see what it says

Normally wouldn’t expect it to get to 55mph in first gear with no problem but I drove it for awhile without it shifting, fluid levels are fine