My car wont go in reverse on 2002 Mercury Mountaineer

last year I had to have the steering column and transmission replaced and the year befor that the cylinoid" spell check" pack inside the transmission pan

Asked by for the 2002 Mercury Mountaineer
can you bring it back to the shop who replaced the tranny maybe still covered atleast 12 months warranty also you could bring it to your local aamco transmission shop for free diagnostic.