Leach, who was fired as Texas Tech's coach in December after he was accused of mistreating an injured player, stopped by Oklahoma State's spring practice as the Cowboys install a version of his high-powered spread offense.
"Obviously coach Leach is not like anybody else," Gundy said. "I've been around him before and I've always had a good relationship with him. That was the first time I'd been around him in a football setting.
"Very informative and a great opportunity for me to learn what was going on when they're out there running his offense and he's sitting there with me."
One of Leach's former assistants, Dana Holgorsen, was brought in this offseason to run Oklahoma State's offense. Holgorsen spent eight seasons on Leach's staff at Texas Tech before serving as Houston's offensive coordinator the past two years.
"It was entertaining. ... (Leach) and I went over the play scripts and he could kind of tell me what was going on because obviously he has a thorough background in this offense," Gundy said. "It was enjoyable. He's always fun to be around and listen to him talk and what he has to say."
The Cowboys ranked among the nation's top 10 teams in offense in 2007 and 2008 before dropping to 70th last season. Holgorsen will be taking over play calling from Gundy, who handled it for the past two years after former offensive coordinator Larry Fedora became the head coach at Southern Mississippi.
"When Dana came in here, we were obligated to let him run his system and he's done a great job with it," said Gundy, himself a former offensive coordinator at OSU. "Our players are comfortable with it and I've enjoyed watching it because it's very new to me, similar to when coach Fedora came here and put his system in. I'm learning it and looking forward to continuing to learn it and see how it works out."
Holgorsen's offense at Houston led the nation in scoring, passing and total offense last season. An early glimpse at his scheme will come in the Cowboys' spring game on April 17.
"I'm staying out of the way," Gundy said. "And as long as we score points and move the ball, that's OK."