Can the leader of a growing night-time radio cult move over to TV without losing the verbal romance that made his radio shows the talk of the East Coast? It appears that Jean Shepherd has pulled it off. The renowned satirist, whose one-man programs are legend in New York, Boston and Miami, now boasts a remarkable weekly bull session called Jean Shepherd's America on PBS-Ch. 17. The telecasts, shown locally Sundays and repeated Tuesdays, vary in subject matter but they always provide a delightful vehicle for Shepherd's imaginative monologues. Tuesday night's show was based on the pleasures of driving - and there was Shepherd, meandering along in his Fiat, extolling the virtues of the open road white lines, pot holes, truck, windshield wipers and steering wheels. * * * * * Part serious, part tongue-in-cheek, he told us: "There are few more sensual experiences than to have a magnificent steering wheel in your hands." Shepherd, who always talks like he has stage-center in the neighborhood bar, compared life's journey to traveling down "the turnpike of existence." A few weeks back, he was waxing romantic about railroads. It's an overworked topic, to be sure, but Shepherd managed to keep it fresh. He even threw in the outlandish tale of his Army buddy, Ernie, who stepped off a troop train to get a beer and was never heard from again. Another recent program literally focused in on food - 30 minutes of tantalizing closeups of the dishes America loves best, everything from broiled hamburger to shrimp creole. Shepherd capped that show with a step-by-step analysis of how to eat a Maine lobster. * * * * * CRACKING OPEN the shell of the tail, dipping it gently in butter, and then chewing and swallowing the tasty prize, Shepherd oozed delight and teased us with "I just want you to know that there's more to life than Hostess Twinkies." The 40-ish Indiana native has become the favorite wit of many urban sophisticates through his late-night conversation piece over New York's WOR. He appeared on several TV talk show but the current PBS outing is Jean Shepherd's first real shot at coast-to-coast television. He looks like he was born for it.