The 49-year-old was found shot to death and wrapped in a sleeping bag in Trout Creek on Jan. 13, 1973, troopers say.
Wimbish was last seen alive leaving work on Dec. 29, 1972, authorities said. He was employed by the Pennsylvania Trucking Company located at 49th Street and Parkside Avenue in West Philadelphia.
His regular delivery route saw him travel as far north as Scranton, Wilkes-Barre, and Stroudsburg, police said.
Before his disappearance, Wimbish had plans to ring in the New Year with a woman in Pleasantville, New Jersey, but she told police he never showed.
On Jan. 23, police found his car, a green 1967 Cadillac sedan, on the 100 block of Duval Street in Philadelphia's Germantown, just blocks from his home.
No evidence has emerged since.
Anyone with information is urged to call the Pennsylvania Crime Stoppers at 1-800-472-8477 or submit an anonymous tip via Crimewatch.
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