Which automatic transmission is in a 2003 Ford Explorer, 4wd, 4.0 V-6, XLT.1fmzu73k73zb18608Thanks?

Which automatic transmission is in a 2003 Ford Explorer, 4wd, 4.0 V-6, XLT.
1fmzu73k73zb18608

5-speed 5R55W automatic
5-speed 5R55S automatic

Additionally, can a home mechanic with considerable mechanical abilities perform an acceptable rebuild on this transmission?

The 5R55W began use in November 2000 for the 3rd generation Ford Explorer and 2001 Ford Ranger. Mostly specific difference between 5R55W (wide shift) and 5R55S (synchronic shift) is a different overdrive planet gear ratio.