When did Jeep discontinue it’s line of full sized pickups?
J10, J15, J20?
The J-10 (1/2 ton) and J-20 (3/4 ton) were last made in 1987.
There wasn’t a J-15. There was the M-715, which was a 5/4 ton military version of the J-series, in the late '60s.
FWIW, The fullsize Cherokee was discontinued in 1983 (when they introduced the smaller one that was still with us until last year), and the big Wagoneer in 1991.
This site has all the information you’ll ever want on the big Jeeps.