yellow 2001

I "think" I'm in the right place to post this. Just bought a 2001 VX yellow. Test drove great. After about 45 miles (and having sat for years according to the owner) the trans started to shift into neutral while in drive; going into 3rd and back to drive fixed it temporarily. I've looked here and see that it "could be" just really low fluid. The mechanic I went to (to change all the fluids and timing belt since I had no records) said the trans was shot and somewhere north of $3000 to fix.
I've lost all confidence in the car. Considering that you all seem to be well versed in all things VX, is $5000 a reasonable asking price for this with 166,000 miles?