Hi and thanks for using 2CarPros.
The problem is related to the transmission, but not because the transmission has failed. Chances are a sensor is failing. When the power control module (PCM) senses an abnormality in the input or output system, the D indicator in the gauge control module will usually blink.
Now, to determine what exactly is happening you need to scan the computer for trouble codes. Here is a quick link showing how a scanner is used:
I realize most people do not own a scanner. Many parts stores will do it for free. Otherwise, you will need to have it checked by a technician.
Once you have it done, let me know what codes were found. From that, I can help you diagnose the problem and give you an idea on repair cost.
Take care and let me know what you find.
Wednesday, December 5th, 2018 AT 8:57 PM