You should use the following procedure for any old military vehicle--especially if the are new or at least new to you!
Just so you know–it is pronounced like “Will liss” and not like something that gives you the willies!

The Willys Quad photo attributed to Chrysler LLC.
Willys’ entry into the jeep race was the Quad. It arrived at Camp Holabird, MD on November 13, 1940. It was not a successful model with the result that Willys was not awarded a contract to produce jeeps until 1941 (after Bantam and Ford).  The Quad was just too heavy to be accepted. This forced Willys to go back to the drawing board and trim the vehicle down to size.  Meanwhile, Bantam and Ford were producing jeeps!
For more about the early Willys,  Bantam and Fords, check out – BANTAM, FORD AND WILLYS-1/4-TON RECONNAISSANCE CARS.