strictly german

First off, I have searched, googled, and searched some more, so please dont criticize me too much.

I've been trying to diagnose an issue with this car for a little while now. Its a 2000 civic ex automatic. Its shifting hard, D4 on the shift selector flashes on ignition and continues to flash, and car acts like its stuck in 4th, no acceleration unless I put it in 2nd, no speedo.

I scanned it with a scanner and its throwing two codes, one related to emissions, and P1768. I'm not concerned with the emissions code as I just replaced a cat on the car, and have a feeling it will clear out on its own. I have narrowed P1768 down to a linear solenoid or a shift solenoid. I could buy both but would really rather not spend the money. Does anyone know what I need exactly based on this fault code?

Also, I've never done tranny work on a honda before. Am I looking at bolt/unbolt or is it more involved for this repair?

Any help anyone can offer would be greatly appreciated.