Sounds like the shift linkage is broken or disconnected somewhere. You'll need to find and repair the problem. Shouldn't be too hard.
The recommended automatic transmission fluid for the 2005-2007 Mustang is Mercon V automatic transmission fluid
The Mustang GT (2011 model) has a 6-speed manual transmission standard and a 6-speed automatic transmission optional. The 2010 Mustang GT had a 5-speed manual transmission standard and a 5-speed automatic transmission optional.
Both automatic and manual transmissions are offered on most of the Ford Mustang models
4R70W
Motorcraft MERCON - V - automatic transmission fluid ( I believe it is stamped into the automatic transmission dipstick )
Type F Automatic Transmission Fluid.
On a 2005 Ford Mustang GT the automatic transmission does not have an automatic transmission fluid level dipstick ( and the manual transmission fluid level is checked underneath the vehicle at the transmission fill plug )
The 1987 Ford Mustang came with a T-5 five-speed manual or optional automatic transmission.
I believe that was an ( A4LD ) automatic transmission with the 4 cylinder engine on a 1989 Ford Mustang
I need a 95 Mustang Gt Automactic what is a match for this and also the right price Thank You
Motorcraft MERCON - V - automatic transmission fluid in the automatic transmission Motorcraft MERCON automatic transmission fluid in the manual transmission ( according to the owners manual )
No , just the automatic transmission has a torque converter