LAW79 - It's great that your are seeking detailed info on what is needed to restore your 3 speed column shifter, but there is one draw back in your post that needs to be edited out and posted in the correct place please and thanks.
smile

Asking "Does anyone have the correct coupling for a 1957 truck for sale..." breaks the forum rules on asking to buy and/or sell things in the Tech Forums. So if you would please edit that out in your original post above then create an ad in the Swap Meet's Truck Parts Wanted forum for what you seek, we can get back to answering your other information questions to help you ID any missing parts and service/adjustment questions.

PS: You can find detailed exploded diagrams and parts listings for your truck HERE as well as column mounted shifter service and adjustment details in Section 7 of the 1955.2 Second Series Chevy Truck Shop Manual. The '57 Truck Shop Manual section 7 covering this info is word for word exactly the same as the '55.2 book. wink

~ Dan
1951 Chevy 3 window 3100
Follow this story in the DITY Gallery
"My Grandpa Carl's Truck and How it Became Mine"
1966 Chevelle (Wife's Hot Rod) | 2013 Chevy Silverado (Current daily driver)
US Army MSG Retired (1977-1998) | Com Fac Maint Lead Tech Retired (1998-2021)