Haha don't it happens to the best of us. Next time you drive it going down the road, push the button on your shift lever, that turns O/D on and off. If it jumps up the rpm's, that means its working and kicking it up into 3rd gear. Push it again and it'll shift back into 4th (O/D). That'll verify that its still working. There's also a little orange light that comes up on the dash that says "O/D off" when you push that button.
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