Hi... My boyfriend just changed the oil on my friends 2004 Toyota Corrola, After... a little while later when she was getting ready to leave the car wouldn't go forward or reverse, so we checked the transmission fluid and it was really low. We added the ATF and it was working fine, but then when we went to drive it to make sure everything was o.k. a huge amount of white smoke (which also smelled bad) was coming out of the exhaust and I think there was oil in the exhaust. All of this happened after a basic oil change?! She doesn't take very good care of her car... like not changing the oil when she should and she doesn't take it in for basic maintenance. We were thinking maybe a blown head gasket?