Auto box won't change out of 1st

As title says won't change up just changed the gearbox filter and fluid and it drove perfect thought it was cured went out last night to a pals came to go home and it wouldn't change out of 1st again 40 mile to get home after 2 miles it changed up perfect and worked as it should all the way home put it in P on my drive and it rolled back so it's not locking up in park. Any ideas appreciated. Atb Ed

not changing up is a common govenor issue on a worn box after oil change, though if you change filter you have to ensure you use 2 o rings, park not working could be incorrect cable adjustment often were cable is secured to mount or broken park wheel

Didn't happen to me but a friend had a similar issue a while back. Turned out the gear selector cable was loose. When lever shows D it's actually in 1 only. Try the cable first. Took a mate 20 mins getting dirty but fixed for free