WJ or ZJ?
I'm looking at getting either a ZJ or WJ Grand Cherokee for a secondary vehicle mainly for ski trips, when it gets too cold to be driving my Cummins, and when I need the extra people space. What are some of the pros and cons to each one? Reliability is my main concern so that I'm not stranded on a mountain in 15-degree temperatures. I know the engines in the ZJs are great, but I don't know much about the WJ’s track record or if one or the other has drivetrain/electrical issues to avoid or watch out for. I'd probably be lifting it to put 31s under it, but looking around at lift kits I see there are many different heights to fit 31s, apparently with quite a few different things to go with them. I'm used to lifting leaf-sprung fullsize trucks and not coil-spring unibody vehicles, so I'm not sure what the best route is for adding the clearance I'd need while keeping good street manners. It's not going to need to articulate a ton because I won't be crawling it, but again, reliability is key. I will also be building a front and rear HD bumpers for it so I’m not sure how much the added weight will affect my lift kit choice. Any and all help will be much appreciated.
Either the WJ or the ZJ would make a good choice for a winter car, as most models have full-time four-wheel drive and all of them have a pretty good heater while being generally very comfortable. You are correct that the ZJ used great engines with either the 5.2L V-8 or the 4.0L I-6. There was also the 5.9L Limited available in 1998 only, which are awesome but hard to find. The WJs had either a 4.7L V-8 or the same 4.0L as the ZJ. The V-8s are pretty similar and produced nearly identical power and torque numbers, though we’ve found the 4.7L to be higher revving and buzzy because it does make slightly less torque. Both are very reliable and long-lasting, though the 4.7L engine delivers better mileage. The 4.0L six-cylinder is fairly legendary in terms of reliability, but the extra heft of the Grand Cherokee made the 4.0L-powered Grands a little sluggish. There were a couple of different transmissions used in both vehicles, but none of them are known to be particularly problematic. The same can be said for the transfer cases, with the notable exception of the transfer case in the 1993-1995 Grand Cherokees, which did not have a 50-50 torque split when in 4-Hi or 4-Lo.
Both vehicles used a Dana 30 front axle with CV axleshafts that can be troublesome. The rear axle in most ZJs is the much-maligned Dana 35, though an aluminum Dana 44 appeared behind V-8s starting in 1996. The WJ also used Dana 35s and aluminum Dana 44s. The 44s are more desirable from a strength standpoint, but they are kind of oddballs because they used C-clip axles and do not share gearsets or differentials with more traditional Dana 44s. Therefore, upgrades are limited for them. Suspensionwise both models are fairly similar in the front, while the rears are different: The ZJ used a four-link with a track bar, while the WJ used a three-link. Both vehicles are good candidates for a Ford 8.8 swap, though the WJ is more difficult due to the three-link and the mismatched wheel bolt pattern (5-on-5 versus 5-on-4 1/2). Both vehicles can clear 31s with a simple 2-inch lift, which can be done with spacers or replacement coil springs. At that lift height there’s really no need for replacement control arms or track bars as long as the factory stuff is in good shape.
It has been our experience that the 1999-2004 WJs seem to be aging a little better than the 1993-1998 ZJs, mostly in regards to the interior. The ZJ interiors tend to fall apart, while the WJs seem to be put together with better materials. The early ZJs are also known to have electrical gremlins. It is mostly for these reasons that we would lean more toward a WJ. They are newer, so chances are better of finding a low-mileage example. Still, if we were in your shoes we would focus more on what you are able to find in your area, as it would be hard to go wrong if you come across a well-cared for ZJ with relatively low miles.