I started the morning thinking that I wanted a CJ. Why not? Metal dash, narrow and short, perfect for the tight mountain trails around here. Simple to repair. Cheap parts, although that is changing. Looking at the examples that were out there though made me reconsider pretty quickly. Given the age the CJ fleet is at now, unless you are doing a restore or a frame-up build, you’re basically looking at a novelty, not something you want to trust eight hundred miles up in Canada or out on the Dalton.
By lunch a TJ seemed like a good idea. Betty the TJ is a fantastic vehicle, rescuing the Land Rover innumerable times while only ever stranding us once (CPS sensor) and continues to be reliable for Victoria, and is still right-sized for the trails out here. In the Wenatchee area, the TJ breezes through the trails that hang up LWB’s and full-sizes.
So I went around looking at TJ’s. The good examples were at dealers, and they weren’t even that good. Rust, and an overriding sense of dampness, and all the little usual things like people leaving the interiors in with leaky tops. Looking at what was out there made me realize that even with a bump or two that Betty was in really fantastic shape.
So by the evening I had bought a 2009 JK w/ 18k miles. I actually didn’t know that much about them prior to this; I had vague notions that the new Pentastar engine was out in 2012, and was as unproven as it was promising with an improved lower RPM torque curve. I’d hopped in a JK once or twice at a dealer and I’d seen them wheel but I had never even looked under one before.
The first few hours the thing seemed very new and shiny and different than the TJ, but it wasn’t long until I realized they are basically just slightly larger TJ’s. If you look over your shoulder at the rear interior and squint your eyes a little you can’t even tell the difference.
So what is different?

The vents are kind of neat. I thought they were weird at first, but they both rotate and angle, which turns out to be a very clever design, probably the best I have seen on any car.

The instrument cluster is updated with a more modern look and easy to see, but doesn’t offer any real improvement over the TJ. Missing is a voltage gauge, something I miss in every truck that doesn’t have one. This isn’t such a big deal, as most amateur radios have them.

The doors are still very basic and detach in the same way as a TJ. They are still held from swinging wide with fabric straps. My JK doesn’t have power anything, but power windows and doors are available on the JK now and this adds another wiring harness you disconnect on each side. Seems like a horrible idea to me, personally, the windows more than the locks.
It’s a mystery to me why someone decided to try to make the plastic look like diamond plate, although I guess that is just an extension of the long trend from automakers of printing pictures of wood and carbon fiber on pieces of plastic to create the suggestion of valuable materials.

The hood mechanics are the same, and in fact, the latches look exactly like the parts off the TJ. I wouldn’t be surprised if they were actually compatible. The hood latch under the hood is just slightly different in design but doesn’t work any differently. The bumpers and tie-down for the windshield are also unchanged, although the JK looks a little odd with the windshield folded down; as a concession I suppose to gas mileage it is curved so does not lie flat on the hood and doesn’t look like it belongs. At least they still leave you the option.

The front bumper sticks out. A lot. Standing in front of the Jeep and looking into the engine, it all seems so far away. The attachment points for the bumper have shifted from the top in the TJ to the front in the JK, and the spacing of the frame is a bit different. Curiously, the bumper that is on this JK is not the one that would have come with it. It has fog lights, but the Jeep didn’t come with fog lights (and indeed does not have the switch for them). I am not even sure if they are wired into anything or not. There’s no sign of a collision and the bumpers on the frame are all perfect, so it may be that someone did it for the looks.
Something about the JK bumpers makes them expensive to replace. It’s common to find high-quality shorty bumpers for the TJ for <$200, such as the LOD bumper that I recommend, but all the good bumpers for the JK seem to be in the $600-700 class although some examples can be had around $450. Almost all the JK bumpers eat the winch (the winch lies between the frame, inside the bumper) rather than the popular mounting point above the frame stubs on the TJ.
I am torn about this design; on the one hand having the winch lower improves airflow through the radiator, but I had an in-bumper winch on the Land Rover and I didn't like it because it made servicing the winch difficult. Basically, if you wanted to do anything with the winch, you remove the entire very-heavy ARB bumper. On the TJ the winch is just right there and very easy to deal with, but is probably also a little easier to steal. I've heard some people intentionally strip their bolt heads or weld a bead around them to hold onto their winches.

The infamous mini-van engine, aka the EGH. This is a modern 3.8 V6 that was first featured in a number of other Chrysler models, including several of the mini-vans, hence the reputation. The upside to that the engine was first produced as a 3.3 for the 1990 model year and bored and stroked into the 3.8 EGH edition for the 91 model year. The engine went variable intake in 2001. Given that it is 20 years old, the kinks, they have been worked out.
It’s also a relatively simple engine; it’s a straightforward pushrod design with nothing particularly fancy going on. Unlike all the prior Jeep engines, the JK EGH’s are electronically governed (including throttle). This is my second vehicle with an electronic throttle so maybe I am used to the computer lag, but many complain about a lack of responsiveness from the pedal, and there are some aftermarket mods to adjust this (basically they amp up the encoder value out of the pedal). Honestly, it seems fine to me, and the thing is practically neurotic it is so twitchy in 4 low.
Another factor that might be related to people’s negative reviews of the engine is that it turns out the JK’s have an electronically governed break-in mode where the performance is limited until some number of miles. Since this one already has 18k on the clock, I have no idea what it was like when it was new.

The engine compartment is busier than the TJ with a bit more wiring but overall it’s straightforward if you look at it for a minute. The JK still seems built like it could fit one of the old I6 4.0s out of a TJ, so there is a lot of room left over between the front of the engine and the radiator. The fan is electric, although for some reason it looks like there’s still a takeoff for a viscous coupler.

The air intake is slightly but not significantly different. It still breaths through a horn above the headlight level. Unlike the TJ, which had the airbox on the “wrong” side of the truck and baffled the air over, the 3.8 breathes centrally and so the intake layout is more straightforward.

The engine affords easy access to the water pump, idler tensioner, belt, alternator, and thermostat. In fact, it all looks completely trivial to change at the side of the road with hand tools and the waterpump looks a lot easier to deal with than on the I6 TJ where there was very limited clearance. I appreciate that Jeep is still including constant tension hose clamps. I love these things, all cars should have them.

The door hinges have a more streamlined design, for no readily apparent reason; now they attach internally in the jam rather than against the tub. The look is a little cleaner but I can’t think of any ready advantage to this.

The oil pan is still ready to be destroyed by rocks, and seems to even hang a little lower on the JK, although I haven’t looked at a TJ that wasn’t lifted + body lifted in a long time. It looks like the identical part off the TJ in fact although I am sure that isn’t the case. The front-end is basically the same as the TJ although it looks like they went to drag link and beefed up the steering rod a bit.

Making up for the simpler intake arrangement on the engine, the exhaust arrangement is truly arcane. The engine exhausts on both sides, and the passenger side manifold exits and goes through some elaborateness to connect to the main exhaust pipe on the drivers side. The drive shafts look beefier than the TJ.

Some of the biggest changes over the TJ can be seen under the JK. The exhaust has been moved to where the fuel tank is on a TJ; the fuel tank then has been switched from a transverse to a longitudal design and placed under the passenger seats, under the tub. This removed a lot of under-tub clearance on the passenger side, and I am sure I’m going to hit that more than twice. It’s protected by a skid guard that is somewhat similar in quality to the one on the TJ and therefore probably not adequate at all for serious rock use. With a design like this I almost would have preferred it if they had moved the fuel tank inside the tub like the Toyota FJ40 although I doubt any modern safety organization would endorse that anymore.
Also hanging under there looking ready to be destroyed is some big plastic box, that looks a bit like a huge charcoal filter. I have no idea what it is for (e.g. EGR or some other purpose), but I’m sure I’ll find out the first time I set it down on a rock.

The rear brake light wiring makes it into the tail door on a TJ through two touch contacts. This is a decent design although sometimes they get crudded up and the brake light doesn’t fire. It took me a minute to realize what was going on with the JK, they ran the wire inside the fabric strap, which is sort of cute.

I wanted a hard-top but ended up with a soft-top, which will probably lead me to buy a hard-top. I don’t like it very much – particularly getting into the back is fiddly. I don’t mind that you have to zip up the rear window so much as the way it mounts into the jeep at the bottom takes more than a moment to do and undo and is relatively fiddly. Maybe this is why I see so many soft-top jeeps with the rear-window removed?

Ah the one thing that is truly better: the seats. I hated the stock seats in the TJ and taking long trips in them was a truly miserable experience. Maybe it was because I was tall or just because of the way I was shaped, but I just didn’t like them at all. These seats are quite comfortable.

Of course, I pulled the interior carpet. You can just pull it out, no tools. Doesn’t even have snaps like the TJ. The thing is that it only takes one or two real offroad trips with some mod and the carpet is basically destroyed and/or more trouble than it is worth to retain. Pulling it now before it is ruined will just let me sell it to someone who cares and actually wants it.

I was very disappointed to learn that unlike the TJ, the paint job in the interior tub of the JK is NOT finish quality. Dear Jeep: What the fuck? Would it really have cost that much more money to fully paint and gloss the inside of the tub? Jeep has also done a weird thing and reinforced parts of the interior tub with strips of weld that looks like they just zigzagged it in with a welding robot after the fact. This is certainly…. curious.
I was also glad I pulled the carpet because there was some dampness, probably from the top leaking, on the passenger side, and just the beginnings of some rust around the drain hole. This is certainly not uncommon in jeeps and is the only real signs of rust I’ve found anywhere on the tub, so I’m happy to deal with it sooner rather than later. A little sanding on both sides and some paint should take care of it.
For the interior, since the paint is crap, I am not sure what I will do, but getting the interior rhino-lined is looking a lot more appealing of an option.

The gangster grill – chrome inserts – easily popped out. No tools required, they are just press fit in with little tabs. They came off neatly and are in perfect shape so maybe I’ll try to sell them to someone who cares. Or maybe find some JK in a parking lot and randomly put them on as a “gift”. ha ha.
I’ve taken the JK offroad (gravel) and the traction control and acronyms are interesting. The ESP is certainly very active, you can’t bomb down a road without it going off a lot. It seems to be effective and I haven’t formed an opinion on whether or not I hate it. You can certainly just deactive it. The Jeep has hill start which I appreciate for wheeling – basically, it won’t roll back for a few seconds when you release the brake on an incline. Since this is a manual, it lets you be a bit lazy to the clutch.
It just has passenger tires on it now, so it remains to be seen how it’ll do offroad. Certainly when I’ve wheeled in groups that had JKs they did very well, but I had such a love affair with offroading the TJ – betty with her auto was just so effortless on the sort of trails we have around here – that it is a pretty high bar for this Jeep to have to match. If anything can beat a Jeep though, it’ll be another Jeep.