A “Screwdriver” is a cocktail of vodka and orange juice. A “Piledriver” (or “Pile Driver”) is sometimes said to be a cocktail of vodka and prune juice (a laxative that “drives the pile”).
 
“Pile Driver” has been cited in print since at least 1959. American actor and comedian Rip Taylor frequently joked about drinking “Pile Drivers.”
 
   
Wikipedia: Rip Taylor
Charles Elmer “Rip” Taylor, Jr. (born January 13, 1935) is an American actor and comedian. He is known for his exuberance and flamboyant personality, including his wild moustache and his habit of showering himself (and others) with confetti.
 
Google Books
Contact Point
University of the Pacific, School of Dentistry
Volumes 36-37
1957
Pg. 19:
They had switched from the Screw Driver (Vodka and orange juice) to the Pile Driver (Vodka and prune juice).
 
3 December 1959, Newsday (Long Island, NY), “Heads and Tales ” by Jack Altshul, pg. 48, col. 2:
Local doctors have come up with a new drink which they call a “pile-driver.” Consists of vodka and prune juice.
 
Google Books
Proceedings
Pacific Northwest Shippers Advisory Board
1959
Pg. 19:
Which reminds me of a new drink we just had today. It’s not a screwdriver, vodka and orange juice. This is called a piledriver and you make it out of vodka and prune juice, (laughter)
           
2 August 1975, Ludington (MI) Daily News, pg. 4, cols. 3-4:
There’s a new drink out made of vodka and prune juice. They call it a Piledriver.
 
27 November 1976, Sentinel Star (Orlando, FL), “Rudy, 75, Wows ‘em Still With ‘20s Nostalgia” by Dean Johnson, pg. E1, col. 3:
“Know what you call a drink with vodka and prune juice?” (Rudy—ed.) Vallee asked them and then answered, “A pile driver.”
 
25 February 1981, The Times-Picayune/The States-Item (New Orleans, LA), “Sammy Davis—still proving he has a ton of talent” by Bruce Eggler, sec. 4, pg. 5, col. 4:
MUCH OF comedian (Rip—ed.) Taylor’s material is scarcely repeatable here, and much of it was scarcely above the level of his line about a drink he said he had called a “piledriver”—vodka and prune juice.
 
26 November 2004, Star Press (Muncie, IN), “Cocktails are making a comeback” by Phil Ball, pg. C2, col. 4:
- The Screwdriver. Made with vodka and orange juice.
- The Pile Driver. Made with prune juice and vodka. Watch out! Stay close to ‘facilities.”
 
Twitter
MrCrispy‏
@MrCrispy
Replying to @greencapt
@greencapt You like screwdrivers? Try vodka and prune juice: that’s a piledriver…
10:47 AM - 5 May 2009
 
Twitter
Weavie Stunned’er‏
@SVNTHLTTR
I had a vodka and prune juice it was called a pile driver lmfao idk why but rip Taylor is hilarious
12:32 AM - 22 Jun 2009
 
Twitter
Brendan‏
@scarface_9toes
Replying to @TheGeneralMH
@TheGeneralMH Blimey, that’s serious. Vodka and prune juice has that effect on me. I call it a PileDriver!
12:50 PM - 7 Jan 2010
 
Twitter
Robert “DCD” Workman‏
@TheDCD
http://g4tv.com/thefeed/blog/post/702304/X-Play-1000th-Rip-Taylor-Visits.html Mixing vodka and prune juice- a piledriver?  :D
10:56 AM - 3 Feb 2010
 
Twitter
Gob Carlqvist‏
@GobCarlqvist
Rip Taylor: ” I’m drinking vodka and prune juice, I call it a pile driver.”
12:13 PM - 16 Jun 2010
 
Twitter
Flush This‏
@flushthis
Why Is The Cocktail Vodka And Prune Juice Called The Pile Driver? http://ow.ly/yE01F
6:02 AM - 1 Jul 2014
 
Reddit—Jokes
I once tried to make a cocktail with vodka and prune juice.
submitted June 4, 2017 by ayresian999
I called it a piledriver.