my '94 automatic 850 will not back up. I have been having some issues with it requiring me to rev the engine while in reverse to get it to go. I flush the fluid every 12-18 mos which always seems to help somewhat.

A couple of days ago i was stopped on a steep driveway and forced to back up the car - it wouldnt reverse and I had to keep revving it and throwing it into reverse to get it out of there - not a good idea, I kno!

Now when I place it in reverse on a flat surface, it shift a bit like I can feel it dropping into reverse, but I rev the car and it wont move. I checked tranny fluid it was down a qt so i topped off but it didnt help.

The fluid looks/smells ok and I dont have, and never did hear any noise. The car does have over 350K miles on the original tranny and i do get a bunch of metal shavings when I flush the fluid.

Would appreciate help as I need this volvo to last a little longer (been saying that for about 15 yrs now)

Should I:
flush fluid
how do I check any linkage
is the pnp switch related?

thanks
mark