[94Stangster]

I got a 1989 4 banger has the a4ld in it and if i put it on the overdrive selector it will go but only if i just drive it easy if i get on it it will slip in all the gears and it never goes in to over drive but if i put it in first it never slips nad same with 2nd and drive it never slips only when i go to overdrive selection if theres a easy fix could you please help i would really appreciate it thanks