There are fault codes stored for the transmission. That is where anyone has to start. Requires professional scan tool to access the codes.

It is Ok to erase the codes, just write them down so you know what they were first. To read the transmission codes on your car, go under the glove compartment and look for a two pin connector located to the lower right of the glove box. Jump the connector with anything metal, cottter pin, paper clip etc, turn the key on and the D4 lamp will blink out the code numbers. >> http://www.google.com/imgres

There could be more than one code stored but it will be up to you to decipher exactly what number is being blinked out. The D4 indicator light indicates a failure code by blinking frequency. This can indicate any number of simultaneous component problems by blinking separate codes one after another. Problem codes 1 through 9 are indicated by individual short blinks. Problem codes 10 through 15 are indicated by a series of long and short blinks.One long blink = 10 short blinks. The number of long blinks = the first digit, the number of short blinks = the second digit.

So if I try to decipher what you blinked it would say code 8 - amd then the single long blink may be a "10" . Additionally, write down what you saw the first time you checked and you can start over as many times as you want until what you are seeing makes sense. Another thing that you will want to do also is to remove the fuse marked "backup" a 7.5 amp fuse for 10 seconds at least and the codes will erase. Then drive the car and see what codes return right away because those will be the codes that matter. Additionally, the same "check connector" is used to blink out fault codes for the engine controls, but the difference is that the "check engine" lamp blinks. The possible codes for the engine begin at 1 and go up to #43 with the same method for reading the codes as the D4 light. Good luck. Start over with reading the D4 light after erasing the codes. Read the engine codes first as well before you erase the first time.