[Paulg390]

Hi, I bought a 1991 SVX a year ago and noticed it slipped a bit when reversing (I.e. engine revs rose but speed didn’t) but it wasn’t too bad. I put it straight into dry storage for a year while I sold some other cars, then last week I took it of storage to find that reverse is a good as useless, engine revs but car doesn’t reverse unless on completely flat ground, slightest incline and no movement at all.
Does this sound terminal for the transmission or should I try oil and filter change first ? All forward gears seem fine... all suggestions welcomed..