Green’s Dictionary of Slang

sled n.

(US)

1. an automobile; occas. second-rate.

[US]R.L. Bellem ‘Beyond Justice’ in Spicy Detective Stories Nov. [Internet] That new hack of mine was a speedy sled. I held it around ninety.
[US]S. Ace Stand On It (1979) 234: This sumbitch is a fucking SLED.
[US](con. 1949) G. Pelecanos Big Blowdown (1999) 143: Su ran a hand along the front quarter panel of his cab. ‘How you like my new sled?’.
[US]G. Pelecanos Shame the Devil 171: I was thinking [...] about how you noticed the pipes on my sled.
[US]J. Ellroy Hilliker Curse 10: The new Buick was a full-dress road hog. It had wide whites and more chrome than the Plunder Road death sled.

2. a motorcycle.

[US](con. 1970s) G. Pelecanos King Suckerman (1998) 100: It sure is a nice sled.

In phrases

lead sled (n.) [‘Originally the lead sled referred to extensively repaired/modified cars due to the use of lead as a body filler’ (Wikipedia)]

(US) a vintage automobile; thence any slow vehicle.

[US] ‘Hot Rod Lexicon’ in Hepster’s Dict. 4: Lead sled – Custom car.
Eve. Indep. (Massillon, OH) 3 July 12/2: The ‘Lead Sled’ has four carburettors and eight exhaust pipes.
News Jrnl (Wilmington, DE) 28 Mar. 45/1: ‘Lead sled?’ I asked [...] ‘One of those big old clunker auomobiles that weighs 4 tons and gets four miles to the gallon’.
Weekender (Wilkes-Barre, PA) 3 July 6/1: This week’s Motorhead Ride of the Week is the epitome of what is [...] referred to by Motorheads as a ‘Lead Sled’.
[US]Baltimore Sun (MD) 16 Sept. B1/1: [[ic. caption] The gleaming engine of a 1968 Mercury Cougar [...] at the Lead Sled Festival.
St Louis Post-Dispatch 10 Nov. B012/2: The beautiful 1950 Mercury coupe [...] is what is known as a lead sled.