The Coventry-built Maudslay vehicle was one of more than 1,700 Maudslays that saw service in the Great War.
Coventry Motor Museum, which bought the vehicle 14 years ago, now needs to raise £5,000 to put the finishing touches to the lorry in time for this summer's 100th anniversary of the war's start.
Used by the War Department for airfield duties in Scotland during the war, the Maudslay had been used as a showman's caravan and as late as the 1970s was in use as a holiday home.
Having been discovered on a Dundee farm, the lorry was bought by the museum for £10,000 and since 2007 volunteers and staff have worked to restore and rebuild it.
At the end of the war the British Army had 66,532 trucks in service, of which nearly half were three-tonners built by companies such as Maudslay, Daimler, Dennis and Leyland.