Transmission is NOT fine. If you have an early 96 this is a sign of trouble to come! Your second gear is going bad. Can not remember off hand the exact issue but you will find posts about this. I know because I have an early 96 with the 4r44e and the truck had been used by a Snow Bird to go back and forth between WI and FL towing a trailer and they toasted the tranny. Sold to me and I thought "No problem. there has to be a million of these" Well not so much. The flashing OD lite is telling you the trans is in default or "limp" mode. Mine started just like yours and at times even shifted normally. By the time it got bad enough that I decided to take it to a shop it was to late, wasn't going to spend $1400 to rebuild it. To determine which trans you have check the door tag on the inside of the drivers door, it will tell you all you need to know about what is in your truck. To decipher the codes just look in here as there is a post that will break the codes for you, gotta use the search. The best advice I can pass along it DON'T WAIT. I got lucky and found a 95 with the exact same trans rather cheap that has never towed anything (no hitch ever put on it, not even the bumper)and even drove it before I stripped it down. There are ways to fit other trans, like the 5r55e, it your truck and there is a write up here some place (search) but hopefully a shop can hook you up if it hasn't gotten to bad yet. Good luck
