The wife's Impala with about 131k suddenly doesn't want to move. It seems to be fine at first when it's cool but after you drive it a little it will not go backwards or forwards. It just revs like it's in neutral. Fluid is more brown than red, has some bubbles and looks like it may be a overfilled. I didn't measure but I'd guess about 3/4 of an inch high on the dipstick. It definitely doesn't smell like new trans fluid but I'm not sure that it smells burnt like I hear people talk about. So is there hope that this is not a huge deal or is it a really good chance the whole transmission is toast?