I have a 96 S-10 4X4 with auto trans. 173000 miles. With engine cold, everything works fine but drive 10 miles and I lose 1st gear. IF you shift from N to D you will feel 2 thunks. it will shift into
1st gear but than right away shift to 2nd gear. IF I stop/restart the car (turn it off), I will get 1st gear once and then never again. If I shift to "1" , I believe I am in 2nd gear only because I feel no thunk when I shift to 2nd.
100% fluid change did not do anything.
Can someone point me in a direction to look at? I can't shake the feeling its some external sensor but I don't know where to look.