I drive a 1991 mercury sable with 107,000 miles and an automatic transmission. within a couple weeks of my purchasing the vehicle the transmission started to slip. i immediately took the car to my mechanic and he said if we catch it soon enough, a flush might solve the problem. i went ahead and took this action. a couple months went by without much of an issue, an occasional slip here and there... that were fairly mild. then on a really hot day day the front seal of the transmission blew. my mechanics said that because the motor is mounted on top of my transmission if would be a very costly fix to pull the motor and transmission and repair the problem properly. because i only paid $800 dollars for the vehicle i opted to go with a cheaper fix. i don't know what he did put he was able to stop the leaking seal and said that he put a very heavy duty transmission fluid to make it last longer... it worked fairly well for 6 months or so before i started having frequent slipping issues again. it mainly happens when i am slowing down and when i am going down hills. it seems to mainly happen on the downshift between 2nd and 1st. but i also sometimes have a problem driving on the freeway. i will be cruising along in overdrive maintaining an rpm of around 2000, when all of a sudden my car violently jerks, revs up to 5 or 6000 rpm and wont go back into gear until i come to a full stop, shut down, and restart the engine. this does not happen nearly as often as when it violently jerks on the downshift between 3nd and 1st but it stills worries me. when the freeway thing happens it does so very suddenly and very hard! it feels like i lost a gear, but all the gears still work. Basically what i want to know is if there is a way to make my transmission last any longer? or am i screwed? as i said i did not pay much for the car so i am looking for cheap fixes! i cannot really afford a new car at the moment so i am trying to make this one last as long as possible! any additives or old mechanics tricks i can use to make it last a couple more months( maybe 6!) would love to make it through the winter at least! to try and minimize the problem i often put the car into neutral and coast to stops. but this is very troublesome when the light turns back to green before i come to a full stop! i have to rev to the perfect rpm before putting the car back in gear or i get a nasty jerk as well! please help with advice you have! thanks!