There aren't too many platforms that lend themselves so readily to just about any task asked of it. Wanna race Baja and win? Wanna rockcrawl the sickest trails at the Hammers? Wanna tow a small boat or a couple motorcycles? Wanna bring five people and camping gear over the Rubicon? Want a comfortable, reliable, economical commuter? Go Cherokee. It does it all-and more. Here are some of the components these little wonders came with and the years in which you'll find them. And, yes, we're still mad at Jeep for killing off one of the best vehicles ever.
Thanks to AMC/Renault's alliance with GM, the 60-degree 2.8L "Omnipuke" V-6 was the upgraded engine option from '84-'86. Most smart folks went for the injected 2.5L four-cylinder instead. These first three years were the only time to get the little 2.5L in the XJ, though, because the venerable 4.0L inline-six became available in 1987. The '87-'90 4.0L was rated at 177 hp and utilized the French Renix injection system. It's a decent system that works well, but is overshadowed today by the'91-and-later high-output Mopar injection system that replaced it. The H.O. engine utilized an improved cylinder head, cam profile, and a better throttle body to bump the 4.0L up to 190 hp and 225 lb-ft of torque. In 1999, a better-flowing manifold and block changes to lessen noise, vibration, and harshness were added. In 2000, the 4.0L went to a distributorless coil-on-plug ignition. These engines are durable, reliable, and can pull 20 mpg on the highway in a stock XJ. As for modifying them, the '91-'93 engines utilized the earlier OBD-1 engine system management that is more easily massaged than the later '94-and-later OBD-II system. However, the aftermarket has come around, and there are ways to eke out really good power from either H.O. engine with positive results. Expect the earlier '87-'90 engines to need a new rear main seal after about 100,000-150,000 miles, but otherwise, the 4.0L engine has the potential to stretch out way past 250,000 miles without major problems.
Transmissions
Early four-bangers used the AX-4 four-speed and later the AX-5 five-speed. They're not the most durable transmissions, but they suffice. Steer clear of the '87-'89 Peugeot BA-10 six-cylinder transmission unless you really enjoy gear work; they're dogs. In 1990, the AX-15 came on board as the standard five-speed and stayed around until 2000. The last XJs got the NV3550. However, it's not likely you'll stumble upon an NV3550'd XJ, but there's nothing wrong with the AX-15. If you go auto in the 4.0L XJs, you get the Asin Warner AW-4 overdrive tranny. It's a pretty durable unit that garners mixed reviews, but we love 'em. They're smooth-shifting, work well off-road, handle a decent amount of abuse, and feature a lock-up torque converter. It's hard to go wrong whether you go AX-15, NV-3550, or AW-4.
T-cases
There were lots of T-cases available in the XJ. The earlier '84-'87 got the NP207, which wasn't a bad case, but parts aren't that easy to come by and there are no Low-range kits available for them, if that's your thing. The NP229 full-time case is best left on the shop floor for what most readers of this magazine are looking to do. As for the '88-and-later Jeeps, the NP231 and NP242 T-cases are keepers. The NP242 Selec-Trac offered the option of 2WD, full-time 4WD, 4WD center-diff locked (for off-road use), and 4WD Low. It's a pretty durable case with decent aftermarket support, but no 32-spline output is available, so if rockcrawling or big tires are going to be used, it's best to swap to an NP231. Every part in the world is available for the NP231.
Axles
The Dana 30 front axle in the Cherokee underwent some changes from its inception in 1984. First, the '84-'99 axles were all high-pinion design. When Jeep decided they were killing the XJ, the company began phasing in the use of low-pinion TJ Dana 30 front axles in 2000. By 2001, all XJs had the low-pinion TJ Dana 30.
The '84-'88 (or so) housings were a central-axle disconnect design. A sleeved tube held a vacuum motor, which slid a collar over a two-piece shaft. The motors can wear out and stop working, but manual shifters, such as the 4XPosi Lock, can be installed. It's actually best just to swap in a later axle with one-piece shafts.
Front axles up through 1994 had smaller 260X-sized U-joints. The '95-and-later models came with Dana 44-spec 297X/760X-sized joints, although the shaft spline count and diameter remained unchanged.
As for rear axles, the earlier vehicles came with the ber-crappy Dana 35. The much better Chrysler 8.25 was phased in starting around 1988. The 8.25 started out with 27-spline shafts, which weren't much better than the Dana 35 shafts, but in 1995, the spline count was upped to 29. Both the Dana 35 and Chrysler 8.25 were available through the '90s. The best way to tell is to check out the diff cover. Both have 10-bolt covers, but the Dana 35 cover is more rounded and looks like the number zero laid on its side with a more rounded top and bottom. The Chrysler 8.25 cover is slightly more squared off and has more abrupt angles at the corners of the cover.
Suspension
There were a few Up Country suspension models made through the run that offered roughly an inch more ride height than the standard model, but by now, most XJ suspensions are going to be slightly sagged and broken in. The rear springs can sag over time, but nearly every manufacturer makes add-a-leaves, lift blocks, lift shackles, and replacement leaf packs for these vehicles.
Up front, the factory control-arm bushings can wear out and crack. Again, aftermarket to the rescue with just about any arm, spring, or shock component you could want. The suspension design remained unchanged through the entire production run, so there's not much more to talk about.
Body And Interior
There were few body changes in the '84-'96 model years. Most notably was a grille change from the first few models. Otherwise, things were stagnant until Chrysler redesigned the Cherokee for 1997 with a more rounded body, better flowing lines, and a nicer (in our opinion) interior. If you're looking to make a racer or want to add wider fiberglass fenders, then the earlier body style has more aftermarket support. For sleeker aerodynamics or just a more modern look, the '97-and-later models have it.
Inside, the earlier models carried over a lot of the AMC/Renault/GM crossover parts. Keys, cruise/wiper/turn signal multiswitches, and even some dash and window controls were General Motors' and proved less than reliable. The earlier interiors are a little more Spartan and dated by today's standards. The '97-and-later vehicles received driver- and passenger-side airbags; a more modern, integrated dash with better switches; window and power door-lock motors; and nicer seats.
Bottom Line
No matter what you're building it for, there's a Cherokee for your plan and budget. The older models are just silly-cheap to get into. When you can buy an injected vehicle with a solid and dirt-reliable drivetrain for under $1,200, there's no room for complaint. Even the later, more stylish '97-and-later models are dropping in price like a meteor. So pick your poison. As long as you stay away from the 2.8L V-6 and the BA-10 tranny, it's hard to go wrong with any XJ.