1997 Honda Civic Transmission jerking and D light Blinking

The car needs to be hooked up to a scanner. It sounds like you may have done that? Is that how you found out about sensor? When a scanner gives a code & says a component is'nt working, that does not mean the component is bad. That is just the begining of the diog. It needs to be diognosed to find out "Why" the component is'nt working. It could be a number of things causing it not to operate properly. Ck. Fluid level? There have been situations where the Trans. Was drained thinking it was the motor oil. Good Luck !