IIRC the military Whirlwind had two systems - Hydraulic or Manual.
The Hyd Pump fitted in the rear of the MGB beside the Generator and both had a rubber damper to absorb Drive vibrations. Often, those dampers would deteriorate and effectively melt in their working environment (very hot and no ventilation) causing a lot of unwanted smoke in the cockpit due to the soundproofing blanket being no help with smoke!
It took about two hours to remove the pump if you didn't know what you were doing, and at least an hour to fit the new one even if you did know what you were doing! Those Vee-Band Clamps were really difficult to do up using a two-and-a-half foot screwdriver.
I seem to recall changing several in fields throughout Shropshire and often mixed with a bit of overnight dossing down in a Bedford JU! As soon as the rodneys left we'd abandon the aircraft and find the warmth of the local pub for a couple of hours.
After an assisted Kip we'd do the job and have a nice camping breakfast of butter-fried eggs, bacon and sausages, and then sit around waiting for the rodneys to return after trying to find where they'd left us.