Speedometer & Odometer not working in 1999 GMC Sonoma SLS ?

[summer_phlox]

6 cyl, 5spd manual. The speedometer & odometer are not working at all. The rest of the gauges work fine. How do I fix this or does the whole thing need replacing? Thanks for your time.

 

[NO WHEELIES :(]

Probably the speed sensor on the transmission needs to be replaced