A pumpkin is an orange gourd generally asociated with fall.
Actually a pumpkin is the slang term used to describe the rear axl differential.. cause its big and kinda round.. like a pumpkin.
I never was 100% sure what the "bolt" rating on rear ends meant.. I always kinda figured it meant how many bolts were holding the cover on.
Refer to the following crude illustration:
[img]
http://www.oldtruckstuff.com/punkin.gif[/img]