down shift problem

I have a 1993 Mercury Sable, approx 150,000 miles 3.0 v6 axod 4 - speed trans axle. problem is when travling down the road the transaxle will take it upon itself to downshift from overdrive to 2nd gear. i'll pull over turn the car off and then start and it'll runn fine. 2-3 sift solinoid has been replaced, fluid has been replaced, computer has been replaced, if anyone has had this similar problem or know what it is please help its driving me nuts. thank you

I would replace the P/N switch. Ours almost never shows a code but can tell when it's bad because of the transmission performance, (irrad shift). Our first transmission went 190,000 but had to replace the P/N switch propably 7 times. One more thing to check is the grounds, one by the battery, one on the transmission bolt, and the plug-in ground connector by the battery connector.

I also believe the best thing anyone could do in owning these cars is to put a transmission cooler on it, a big one! Some transmission shops won't warranty there work unless one is installed. They just get to hot.

Do you have the axod-e or the ax4s? The ax4s used the axod-e pans when they first switched over in the 93.

About any kind of erratic transmission problem on Sable.

There is a switch, which is sensing RPM and controlling tranny shifts. Replace this one.

I had a problem, took my car to dealer and he wanted to replace whole transmission. Then took it to local transmission shop and replaced this switch within 20 min including diagnostic and two test drives. This switch is on the top and easy to replace.

I saw a lot of complains about transmission on this site and I know this switch will fix most of them