75 cruiser

Hey Guys.

My speedometer suddenly quit working, plus I am now getting error code P1790 (or P1791).

I have looked up the error code, but all I can find is it's transmission related. I figure the speed sensor is mounted on the transmission, so replacing it should take care of the problem.... I think. The gear changing hasn't been affected too much, but it does sometimes shift a bit hard.

Anyone had the same experience? And, if it is the speed sensor, where on the tranny is it located, and how difficult to replace?

Almost forgot. It's a 1998, 3.2TL with 190K miles.

Thanks for the help.