Meridian Rack & Pinion, doing business as San Diego-based, said it was acquired by private equity firms and the company’s management team.

Gladstone Investment Corp., a Virginia-based business development company (Nasdaq: GLAD) said it invested $13 million in a combination of debt and equity, along with Digital Fuel Capital, a private equity firm focused on e-commerce and digital marketing, and Meridian’s existing management team for the acquisition.

A Gladstone affiliate, Gladstone Capital Corp., also participated in the deal, providing $5.6 million of debt and equity on the same terms as Gladstone Investment, according to a company announcement.

Jean-Pierre Gilbertz, Meridian’s founder, continues to hold a “sizable stake” in the company, the announcement said.

Founded in 1989, Meridian is a seller of aftermarket and original manufacturers’ auto parts through wholesale and online channels.

The business was ranked No. 75 on the San Diego Business Journal’s Fastest Growing Private Companies List last year based on its revenue growth from 2010 to 2012. In 2012, it did about $34 million in sales, and was on track to hit about $42 million in sales last year, the business said.

Last year, the company said it had 118 employees, up from 75 in the prior year.