1999 Mercury Sable

Transmission problem
1999 Mercury Sable 6 cyl Front Wheel Drive Automatic 91,000 miles

I have a 1999 Mercury Sable LS with 91,000 miles, V6 front wheel drive and auto transmission. I stopped driving it about 2-3 years ago(no problems with it at time), moved it around from the garage in the winter to the driveway in summer, started it up monthly and drove around 1 street in neighborhood briefly every 3 months. The battery was disconnected inbetween starting up. Recently while taking for drive's in neighborhood it shifts hard, revs up to about 3 to 3500 before shifting, through lower gears(can't get speed up through more gears as only trying on a short neighborhood street, not registered for road currently) was slightly smoother shifting when shutting of o/d. Transmission fluid level is ok. Any suggestions?
March 22, 2010.

Chances are there is a problem with a shift solenoid. It may go away after driving it for awhile. The worst thing you can do to a car is allow it to sit.

Thank You. Where would I find the shift solonoid, and procedure to test it?

Mar 23, 2010.
THey are located in the transmission under the transmission filter. Usually, (not always), they will set the check engine light. Has that ever happened? As far as testing them, you need to remove them and check resistance.