On either side of the catalyitc converters.
4
4 sensors total. 2 upstream on either side of exhaust manifold, 1 left side downstream, 1 right side downstream.
4
4
One
two
2
TwoTwo
OneOne
Two
The 4.7L 2002 dodge durango has 4 O2 sensors. ref. Chilton's Dodge Durango/Dakota 2001-03 repair manual. page 6-19 (Oxygen sensor - general info and replacement) The upstream oxygen sensor is located before the catalytic converter. The downstream oxygen sensor is located is located after the catalytic converter.