Forester 2009 noise and hard to turn right and left such as diff lock

Hi I have a Subro 2009 Model 2.0 petrol 4 × 4 When I turn right or left at low speed I feel heavy auto and hear the sound of a splash. As if the vehicle is locked in the differential. What solution did I see on sites that have changed kit to Differential and did not emphasize whether it is rear or front