**Speed Sensor**

So...In doing a little research I see there is 2 sensors in the trans case...my truck speedometer has been working but when i put it in cruise it surges...like it is roaming to fing the right speed and the mph go 3-5 mph up or down from the mph I select.

So, I am not sure IF it is a speedo sensor or which one even....I drained my tranny fluid to change it and a chunk of plastic, or two, did come out....

any ideas?

Thanks