I have a 1994 Mercury Grand Marquis with I believe to be the AOD-E transmission. The transmission failed completely, and I had a transmission shop rebuild it for me. Twice I have gotten the car back, and it would drive okay for a few days, and then would start to act up. Either going from park to drive, or while stopped at a light (in drive) ,it will seem to be in neutral for a few seconds, and then will slam into gear after i give it a little gas.
They have had it apart at least 3 times now, and I am curious as to what is going on. Obviously, they are missing something, and they are redoing it under warranty, but I am getting tired of their not being able to repair it properly. Can anyone in the automotive field clue me into what they are doing or not doing properly?
It is of course very difficult to diagnose something like this over the net, but I have some ideas…
The gears are engaged using hydraulic pressure. Where the hydraulic pressure goes is controlled by what is called the valvebody. With your tranny being a -E, it means it has an electronically controlled valvebody.
So I can see it being either a hydraulically related problem, or electronic.
Hydraulic problem could be a blocked passage, a faulty valve, or a bad pump. Reving the engine will increase the hydraulic pressure which could make a valve move to the correct position, or overcome a partial blockage.
Electronic problem could be the actual computer controlling the transmission, the wiring harness or the electric solenoids located inside the transmission which direct the fluid.