A/T lever not loccking

[Snake1]

guys.. I hope you can help me. i have an AT toyota townace with no previous transmission problems. This afternoon i parked at an inclined gravel parking with the front downwards. I engaged the P lever and the hand brake.

After runnenf som errands, I was back in 30 mins.... after starting the engine engine.. i proceeded to shift to D.... ayaw na mag lock ng level.... meanin you can easily move the lever from D-2-L with out exerting any effort. It doesnt lock in the individual drive slots. Ok naman ang hila and it still shifts automatically....

What do you guys think couls be the problem....? Im worried cuz now you can move the level with a finger and it might shift into a different gear accidentally while in high speed....

any advise or insights on the matter

[Snake1]

Up lang po....

anyone have an ideas on this...? kaya ba ito ng DIY?