Hi all
i have a 2001 s40 2.0 se , current odometer 82000 km
bought a month ago

i have noticed the car suddenly drops down to low gear if i release my leg off the gas pedal and struggles to high rpm and slows down , it doesnt even keep its momentum !

I did a engine oil+ filter change and transmission oil change

can anyone give me an idea what could be wrong? The only warning i saw is transmission arrow stays lit upon ignition on and goes off as i start the engine
thanks