Fleet sales will be moved to the group's Coventry site which is set to expand after running a series of pilot fleet sales for a host of leasing companies.
Manheim Gloucester is set to double its number of commercial sales from 15,000 to 30,000 following the refurbishment, which will begin over the next few months and is due for completion early next year.
John Bailey, chief executive of Manheim Auctions, said: 'This expansion for Manheim Gloucester is excellent news for buyers, vendors and staff as it allows us to transform facilities on the site and develop it into Europe's leading commercial vehicle auction.'
The investment will see the Gloucester site expand from a 10-acre site to 15 acres. It will also include refurbishment of the auction buildings, new road access to the site, a new drop off area, new entry control facility, car park re-surfacing and a new valeting facility for commercial vehicles.