Well if you're doing your standard fluid/filter change, just measure how much you removed, and replace that much.
On a 1997 Mercury Tracer : The AUTOMATIC transmission fluid dipstick would be on the side of the transmission ( transaxle ) in the area of the brake fluid reservoir . The manual transmission ( transaxle ) does not have a dipstick
4.1 Qt.s
According to the 1997 Mercury Tracer Owner Guide : For the automatic and manual transaxle ( transmission ) ( Motorcraft MERCON Multi Purpose automatic transmission fluid )
Dexron/mercon
Should be a plug at the side of the transmission- fill to this level
On the 93 escort, brother to Tracer, there was only a breather valve at the top of the transmission and fluid needed to be added by removing an access bolt OR it had a small yellow dipstick at the top of the transmission.
Down the tube that holds trans dipstick.
I believe it's dextron/mercron II
To add transmission fluid to a 1999 Mercury Tracer, locate the transmission dipstick tube, which is typically found near the back of the engine bay. Remove the dipstick, use a funnel to pour in the recommended type of transmission fluid, and check the fluid level using the dipstick to ensure it’s at the correct level. Be sure to add fluid gradually and check frequently to avoid overfilling.
Auto: fill through dipstick tube Std. Plug at side of transmission - fill to this level
I have a '93 ford escort 1.9, I always use mercron automatic transmission fluid. Use Mercon but do not use Mercon V.
The fluid should be at the top of the cross hash marks.