Columbia odometer problem.. Ideas?

I have a 06 Columbia with a 14L Detroit. I replaced the seal on the rear of the transmission today and now my odometer is flashing. It reads fine, and the speedometer reads fine but it continually flashes. Only thing I had to do was drop the driveshaft and unbolt the plate on the rear of the tranny to replace the seal. I did attempt to lightly remove the speed sensor, it is mounted on the back of the trans aiming down to the top of the driveshaft , but It was froze and would not budge. I'm going to crawl back under it and check things again, but I haven't heard of this before.. Thanks in advance for any ideas!