slipping & jumpy auto gearbox in my J reg 1.6 Escort?

hi, the Auto box in my car has been jumpy on warm take off for a few weeks, today it started "slipping" reving high and gradualy creeping forward, making a metalic noise. could it be an oil change reqd or something far worse
the gear stick layout is P R N D L i belive this denotes which type box fitted
regards Neil