Drive, No Drive??? Reverse, No Reverse???

[FXSTCHIEF]

Yes, I ensured it was full. I even added some anti-slip fluid (lucas) to see if it might rectify the problem. No changes in the behavior have been noticed yet.

I just bought this vehicle with no known history of it's maintenance. Is it possible that the tranny filter is partially clogged? Would those same symptoms be evident from a dirty filter? The vehicle has 138,000 miles on it and I don't know what all has been done before.

Thanks!