Passenger side rear of engine
the transmission could be going out or slipping or your transmission fluid could be low
rear passenger side of engine
Rear of engine near firewall.
I believe that the type of fluid to use is engraved into the automatic transmission fluid level dipstick
The transmission dipstick is located at the area close to the firewall on the left or passenger side of the vehicle in the engine compartment. The dipstick is used to check the level of transmission fluid in the vehicle.
Mercron transmission fluid is used in a 1978 Ford Thunderbird. Type F fluid can also be used but should not be mixed.
On a 1996 Ford Thunderbird : Through the automatic transmission fluid dipstick tube ( using a funnel ) The dipstick is located near the firewall , in the engine compartment , on the right side of the engine ( passenger side )
You will refill the transmission fluid in 1990 Thunderbird in the fluid case found in the bonnet of the car. You should ensure that it is about 1/4 inch below the fill plug hole.Ê
if it is using trnasmission fluid you could have a bad tansmission modulator. take it to a shop
According to the 2003 Ford Mustang Owner Guide : 4.6 liter manual transmission ( MERCON automatic transmission fluid )
The 2002 Ford F-150 owners manual shows Motorcraft MERCON automatic transmission fluid for the 5 speed manual transmission
Look in the manual