Hi again smoking rocks...I agree....in my case, I am getting a DTC 81 with the autodiagnostic funtion, represents "open circuit between ECM and TCM in the ECT1 unit" says....also I discovered I have the number 63,65 and 86 DTC s for the electronic trans..fixed the speedo, but also a lot of other issues remainECT functioning propperly means the transmission is getting power and signal. Did this happen before you replaced the filter?
Have you pulled your engine codes? some may be on without illuminating the CEL.
I'm thinking there is a communication issue between the ECU, TCU and transmission when selecting drive, so I'd focus on that electrical pathway