Yes, it is a rebadged version of the Ford Explorer.
If you have a 1997 to 1998 Mercury Mountaineer or Ford Explorer with a V8 engine, you will have a 4R70W transmission.
If you do a Google search online for 2002 Mercury Mountaineer ( Ford Explorer ) there should be reviews to read
Starting with the 2002 model , there is no automatic transmission fluid dipstick on the Mercury Mountaineer ( and the Ford Explorer , 4 door )
The same vehicle so only difference is the badges
I assume the 2002 Mercury Mountaineer would be the same as a 2002 Ford Explorer ( No , starting with the 2002 model there is no automatic transmission fluid level dipstick ) Ford has a way of checking from underneath the vehicle
If you do a Google search on Ford Explorer blend door there are lots of articles
On a 1997 Mercury Mountaineer : I assume the fuel filter would be in the same location as a 1997 Ford Explorer : ( underneath the Mountaineer , below the drivers door , mounted on the frame rail )
It should be in the right front passenger footwell , by the kick panel ( that's where it is on a Ford Explorer ) O.K. you got me ! - I forgot that the Mercury Mountaineer started with the 1997 model year
I was looking at the 1998 Mercury Mountaineer Owner Guide and it doesn't give the answer , but it should be (79.5 litres / 21 U.S. gallons or close to that , like it is on my 1995 Ford Explorer XLT )
The 2004 Mercury Mountaineer does not have an automatic transmission fluid dipstick . I know that the 2002 and newer Ford Explorer four door versions do not have a dipstick for the automatic transmission fluid level .
According to the 2000 Mercury Mountaineer Owner Guide : ( Yes , DOT 3 brake fluid , meeting Ford specification ESA-M6C25-A )
I'm not a mechanic / technician , but I would say ( no ) if you mean the six cylinder engine The 1996 Ford Explorer V6 is the 4.0 literEFI ( which is an Over Head Valve / pushrod design engine ) The six cylinder engine in a Mercury Mountaineer has always been the 4.0 liter Single Over Head Cam ( SOHC ) version