I served my apprenticeship with Streets Ice Cream, at Turrella, and the White in your photo, in issue #30 of Vintage Trucks and Commercials Magazine, was one of the vehicles that I worked on during my five years in the workshop. I remember that the White had a large hydraulic pump mounted on the left-hand side of the engine, and hung out over the mudguard. This pump was a constant belt-drive off the crankshaft, and ran a hydraulic motor, via large diameter hoses. 

The motor was mounted under the trailer, and this drove the refrigeration c