I have a 1984 with a automatic transmission, 52,000 original miles.
one day all of a sudden I had no 3rd or overdrive, it would shift in to those gears but not move just rev up. 1st and 2nd work fine and the fluid looks and smells normal.

I have had plenty of GM's over the years but never lost a tranny at 52,000 miles.

any ideas???

thanks in advance

 

I have an idea, which i$ not good, but it might not be your problem.

On the 700R4, the clutch bands are the same for 2nd and 4rth (OD), and they get used twice in each shift cycle. That's why GM says city drivin' in '3'. 1st and 3rd have their own bands.

Are you sure your '3rd' is gone? Maybe you're missing 2nd and 4rth?