1998 Ford Mustang Q&A
1998 Ford Mustang Question: what will happen if the transmission fluid is overfilled by a quart or more?
Fluid level should not be over filled as over a period of time it could cause fluid leaks at pump seals. If you are having problems with no forward gears 1 qt of fluid would not cause that issue. May want to check with supplier of transmission and get advise from them on your problems...check to see if in warranty. - milesauto
most likely it will blow out your overflow and cause fluid leaks - globalhelper