1996 Mercury Sable Transmission or something else?

I have a 1996 Mercury Sable. The engine light is on. I have been driving it with this problem (I know) for 70,000 miles. it is an automatic transmission. When the car is on and I am getting resdy to accelerate I have to put it in 2nd then once i get to a certain speed I can put it in drive and it drives fine. But then when I slow down again at a light I have to do it again. The weird thing is that on the rare occasion it rains for some reason I don’t have to do this manually it goes from drive. Anyone have any idea what the problem is. I don’t know what the codes are. But like i said it has never gotten any worse in the 70k miles i drove it this way. It has about 160k miles on it now.

You must live somewhere with no emissions test.

If you’ve been ignoring the check engine light for 70K miles there could be (is) more than one problem.

You really need to have to code(s) read.

Has the transmission fluid ever been replaced?

It may have been but i honestly cant remember if it had it would haven been many years ago. I plan on changing the filter and oil this weekend as I just did this on another car. I just wanted to see if maybe it could be something else other than trans. If the tranny what specifically could cause that. I am gonna get the codes checked as well. but wanted info before I take it in as so many shops just lie about trans and tell you to replace or rebuild. Since it never got worse i thought it is a good thing.

“Since it never got worse i thought it is a good thing.”

I admire your optimism, but a transmission that may not have had its fluid and filter changed in 160k is likely to be in very bad condition. You should definitely go ahead and do the fluid change (coupled with dropping the pan and cleaning it out), but don’t be surprised if the transmission fails soon anyway.

As to the CEL, since you have been driving this car with that light lit up for 70k, there are likely to be MANY codes present. Be prepared to do a lot of work on the engine and the emissions system, in addition to the transmission.

Well the light came on about 4 years ago. I had it checked I can not remember what it was but they replaced something in the engine, not a big deal, cheap as I remember it. But it would last a few days then the light would come on again so I would take it back they would check the code and replace the same thing. This happened about 4 times. I never noticed anything wrong with the car at that time. I finally gave up and stopped having it checked. I can not remember what it was. So the light being on became normal it was later that the tranny started to have problems with first gear. Anyway I know I let it go but i never intended to keep the car we were going to donate it. We have since decided to try and fix it up instead. If worse comes to worse we will go ahead and donate it. It is drivable and has no other problems. It need front breaks so we will be replacing those this weekend then doing the tranny fluid and filter and clean the pan then see if it still has problems. I am not actually the one that drives the car so this is probably why it is in such disarray. I cant drive a car like that it would make me have anxiety. However I am trying to take care of it now. If you think you know what might be wrong with the trans from the symptoms it will at least give me a start. When I get the codes checked I will post them here.