Brad Fritsch posted a 4-under 68 in the third round to move into a tie for second. He was joined at 11-under-par 205 by Stuart Anderson (69), Mike Grob (70) and Ryan Miller (69). Iain Steel and Andrew Barnes are one stroke further back at minus-10.
Gangluff, whose lone win came last year at the Lewis Chitengwa Memorial Championship, opened the day six shots off the pace. However, he stuck his second shot within 3 feet of the cup at the first and birdied the hole.
He collected two more birdies on the opening nine on Del Rio Country Club to move atop the leaderboard as overnight leader Pat McDonald struggled.
Gangluff posted two more birdies on the inward nine to secure the third-round lead.
'It's been a lot of fun and my game is feeling really good right now,' Gangluff said. 'I'm just trying to get it in the hole and move on to the next tee. It's easy to be comfortable when you feel you are in control, and that is what it's like for me right now.'
Fritsch moved into second place with his 68. After tripping to a bogey on the second, he carded four birdies. He then moved within one of Gangluff by draining a 30-foot birdie try at 16. That put him in the final pairing for the first time in his career.
'I was happy that I didn't give one back on that last hole,' said Fritsch, who two-putted for par from 65 feet out at 18. 'I've never had a chance to be in a final group out here, but I know Stephen pretty well. We should have a lot of fun. I think I'm ready to win. Now I just have to get out there and do it.'
McDonald was on pace to become the oldest winner in Canadian Tour history. Unfortunately, he celebrated his 55th birthday by struggling to a 4-over 76. He dropped into a tie for eighth at 9-under-par 207 alongside Brien Davis, Jon Turcott, Matt Hansen and Casey Martin.