Jim, I'm going to take a guess at this and say that your 37 is like my 46 in that there are no adjustments in the hinges.
With the 41-46 trucks you have to actually tweek/bend the hinges. This sounds worse than it really is. It involves putting a block of wood in the hinge and closing the door on it to tweek the hinge and move the door the direction you neeed.
If you want to try this, email me directly and I can send you scans of the procedure from the GMC truck service manual. I think it should work for your 37.
George
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