still wont shift gears.. any clues ? ?

So i bought an auto 93 cougar xr7 a few weeks ago, it was driving fine except the gas pedal seemed to be feeling like it has less resistance and was touchier up to a certain point. The real problem happened when i was on the highway and was pushing about 5 RPM and only going 40 mph, and it has happened multiple times, im pretty car illiterate and my grandpa helped me bring it to the shop and talked to the mechanic ( my grandpa knows what he is doing ) so the mechanic checked it over and it needed a new tranny, put a new transmission in, and now its still doing it problem wasnt fixed? what could the problem be? thanks for the help, i appreciate it.

ALSO, my stereo shut off and wouldnt turn on a few minutes before the first " wont shift gears going up this hill " incident, could it be something electrical? tried to fix it many different ways and couldnt..

, put a new transmission in, and now its still doing it problem wasnt fixed


Welcome to AF

Well, this is a serious problem right here. How much did the mechanic charge for the transmission? Did he really do the work? (ie does the transmission look new and clean?) They are not cheap and is obviously it was not needed if the problem still exists.

These cars shift electronically and rely on a speed sensor to tell how fast the car is going. If the sensor does not work, the transmission will not shift.

IMO if the new transmission did not fix the problem, you should not have to pay for it; and he owes you your money back.

Fortunatly, I should get a full refund. ( $700 total ) My grandpa found me a used transmission from an old friend who also put it in. He gave me a 91 day warranty so if it is not the transmission I should be set. Would you know what the sensor is called? I figure there is more then 1 sensor. thanks!!

Would you know what the sensor is called?

Well my post called it a 'speed sensor' which is what it actually is called:
http://www.1aauto.com/1A/SpeedSensor/Mercury/Cougar/1ATRS00003/489444