Reddick, who drives the No. 45 23XI Racing Toyota, ended up with the fastest average lap speed at 162.250 mph.
Reddick was fastest when teams initially went out on the track during the 50-minute session and later when most teams changed over to qualifying set up.
Truex ended up second-fastest (161.407 mph) and Ross Chastain was third (161.369 mph).
Erik Jones and William Byron rounded out the top-five.
Completing the top-10 average lap speeds were Bubba Wallace, Denny Hamlin, last year’s race winner Chase Elliott, Chris Buescher and A.J. Allmendinger.
Among those drivers who ran at least 10 consecutive laps, Reddick also had the fastest average lap speed (160.400 mph). Chastain and Truex were second and third, respectively, in that category.
About 35 minutes into the session, Kyle Busch spun off Turn 4 and down the frontstretch but avoided any contact with the wall.
Busch took his No. 8 Chevrolet immediately to the garage after the incident.
There were no other incidents during the session.