The Chadderton site became a stand alone used-car operation, branded Pentagon Car Shop, late last year following the successful amalgamation of the Chadderton Vauxhall dealership into the group’s £4m purpose-built Vauxhall and Saab showroom in Oldham.
But the business has not yielded the expected returns, said Pentagon spokesman James Reeve.
He added: "This latest initiative to develop the site as a Vauxhall Commercial Vehicle and Business Centre again underlines our commitment to Vauxhall vans."
Pentagon will move its existing business centre in Park Road, Oldham, to the Chadderton site, which will house six to eight new vehicles in the showroom plus up to 50 used vans on the forecourt.
The dealership also incorporates an 8 bay workshop and there are plans to redevelop the existing bodyshop.
Pentagon will also open a LCV showroom in Sheffield next month, stocking around 20 vehicles in the showroom and with space for 50 used vehicles outside.
That site will include a 20 bay car and van service centre and a 40 bay bodyshop.
The group's Vauxhall and Chevrolet car sales departments in Sheffield will also move to a new location just 200 yards away from the existing site on Savile Street by October.
Reeve said Pentagon Group started 2008 strongly with new and used cars sales up 4% year on year and half-year profits only slightly below those of the same period in 2007.
The Group currently has motor dealerships located in Derby, Burton, Ashbourne, Oldham, Rochdale, Mansfield, Nottingham and Sheffield, carrying the Vauxhall, Chevrolet, Peugeot, and Saab marques.
Pentagon Car Shop Barnsley is a used-car operation and a Chevrolet dealership.