Which All-New Car Was The Biggest Leap Forward Over Its Predecessor?

Recently I was thinking about how laughably antiquated my Jeep J10 pickup truck feels compared to my other Jeeps, especially my Jeep Grand Cherokee. Then I realized something absurd: The still-surprisingly-modern Grand Cherokee was the direct successor to the J10’s platform-mate, the also-absurdly-antiquated Grand Wagoneer. And the quantum leap between that 1991 Jeep Grand Wagoneer and the 1993 Jeep Grand Wagoneer successor is a leap like few we’ve ever seen in auto history, so let’s talk about it.

For today’s Autopian Asks, I initially had in my mind the Jeep Cherokee XJ, and just how enormous a leap over its processor it was. The “SJ”-platform Cherokee was a heavy body-on-frame design, with a fully leaf-sprung suspension, and outfitted with gutless carbureted AMC straight-sixes or AMC V8s bolted to three-speed slushboxes or four-speed manuals (some had five-speeds, but they’re rare). The XJ was 90 percent as big inside, despite being so much smaller outside, and also weighing over 1,000 pounds less. That’s truly absurd, but it was thanks to the then-state-of-the-art unibody construction (contrary to what you might find on the web, the XJ was not the first high-volume unibody SUV; that honor, I think, goes to the M151 MUTT military vehicle that went into production in 1960).

Add a unique quadra-link front suspension and better overall off-road geometry, and the XJ was leaps and bounds ahead of its predecessor. The only issue was: The available engines and transmissions were terrible.

That’s a part of the XJ’s history that many tend to forget about. Between 1984 and 1987, the XJ was a bit of a steaming pile when it came to engines and transmissions. The GM-sourced 2.8-liter V6 was a reliability nightmare, and honestly the 2.5-liter AMC motor was better, though both were gutless carbureted SMOG-choked motors. Even when the 4.0-liter fuel-injected motor showed up for 1987, it was bolted to a terrible Peugeot BA10/5 five-speed manual transmission (though the AX15 auto was good).

So yes, in some ways the 1983 to 1984 Jeep Cherokee jump was huge, particularly when you look at the body structures, but it wasn’t as huge as the 1991 to 1993 Jeep Grand Wagoneer jump.

Technically I’m bending the rules a little here since the 1993 Jeep Grand Wagoneer is technically a “package” that you could choose when you bought a 1993 Jeep Grand Cherokee, and technically that’s two years after the Grand Wagoneer left the market. Still, two years isn’t that long, and there’s no doubt that if the XJ was the successor to the Cherokee, then the Grand Cherokee was the successor to the Grand Wagoneer, which left the marketplace in 1991.

The leap between the two was unbelievable. The Grand Wagoneer was a fat, slow, downright ancient machine by 1991. Its AMC 360 engine made torque, but very little power, and was a handful to maintain (relatively speaking).

The Grand Wagoneer was completely different, and better it almost every way. Its fuel-injected 5.2-liter V8 (based on the “LA” Chrysler 360 and not the AMC 360) made 220 horsepower and 285 lb-ft of torque — 76 horsepower and 5 lb-ft more than the old Grand Wagoneer. And on top of that, the chassis was a unibody one with Quadra Coil — an industry-first fully-four-link-coil-sprung-solid-axle suspension.

Though the four-speed automatic versus the three-speed in its predecessor wasn’t a huge leap (especially given the four-speed’s reliability issues), the significantly more powerful and reliable engine, along with the >500 pound lighter unibody structure, along with the significantly improved suspension made jumping from an SJ into a ZJ like stepping into the future.

Add airbags, ABS brakes, and just a totally more modern cabin, and the two couldn’t be more different. I can tell you, after owning two Grand Wagoneer and a handful of ZJs: The ZJ is better in every conceivable way except styling.

Top graphic images: Bring A Trailer; Jeep/Ebay seller