8.3L - Upstream 1/1, 2/1

Raise and support vehicle.
Disconnect heated oxygen sensor electrical connector. See Fig 1.

Fig 1: 2/1, 2/2, O2 SENSORS (Right Side)
Courtesy of DAIMLERCHRYSLER CORP.

1 - Upstream O2 Sensor

2 - Downstream O2 Sensor
Remove sensor using an oxygen sensor crow foot wrench such as Snap-On tool YA8875 or equivalent