Speedo - OD quit

[chief2]

Was driving the truck today and I notice the speedo not working. Then I see the OD light on the shifter is flashing. Acted this way for about a mile then everything ok. Anybody got any ideas what I need to look for? Thanks.
Gary

 

[Scarlet_Nape]

Chief, check this link.

 

[chief2]

Thanks. I bet that is it!