This may sound stupid but is it possible to bolt a rear cover on wrong? I have an 89 GTA with a nine bolt rear end . The rear cover has a plug in it. When I took the rear out to clean it ,inspect it inside ,change seals and paint it I put the cover back on and thought nothing of it. Last night I went to fill it up with gear lube and posi additive and it did not seem to take much at all before it ran out the hole and I can not remember how high up the cover the plug was.(it's been out of the car 2 years during build up) The plug seems low to me. Can this cover be bolted on upside down??

 

It will only fit one way. It takes 1.8 quarts to fill it.