Slocum fell out of sole possession of the lead when he missed a short par putt at the 18th hole.
Slocum fired a 70 as both players finished with a 54-hole total of 15-under 201.
Mike Heinen, Carlos Franco of Paraguay and Mike Hensby of Australia shared third at 202, with Per-Ulrik Johansson of Sweden, rookie Vaughn Taylor and Bill Glasson at 203. Harrison Frazar and rookie Dan Olsen were another stroke back.
Twenty-five players were within seven shots of the lead, vying for the $540,000 first prize.