Just bought a 2012 Elantra AT with 237k on it. Owners manual states transmission fluid change( drain and refill) at 240k. To do or not to do? I have no real service history of this car.

Transmission right now is okayish. Kinda clunky going from park to drive sometimes, which has gotten better since I changed my oil last week. It kind of lags while going through the gear selector too, most noticeably on park. If I switch to park and let go of the brake too quickly car starts rolling backing for a second and then locks into park.

Any advice?