Speed Sensor Question

[Stringer]

Does a speed sensor go bad all at once, or can it go in stages? On my 90 Suburban 4x4, 350 auto, 1 to 2 shift has often seemed labored for a while. Now the speedo is out. Just wondering if it's related.

[carguy499]

speed senser only sends a signal to the ecm to operate the speedo as well to set parameters ie: timing it does not shift the tranny in a 90. Im assuming you have a 700r4 trans?

[Stringer]

700r4, yes. I finally found the capacitor on the back of the speedo was shorted and blown. Posted about the fix I and a neighbor did. I'll still need to check on the shift, but the speedo's working again. Thanks for your reply.