TJ WRANGLER

The Wrangler TJ was first time introduced in 1997 after one year no production gap from its prodecessor YJ. This updated Wrangler featured a coil-spring suspension (based on that of the Jeep Grand Cherokee) for better ride and handling, and a return to the CJ's iconic round headlamps. A new dash modernized the cabin upon its debut, while dual front airbags and the option of antilock brakes made it safer, too. Of course, all the ingredients (such as generous ground clearance, skid plates and a crawl gear for the transfer case) that made the original CJ so capable off-road remained. The engine is the same 4.0 L AMC Straight-6 used in the Cherokee and Grand Cherokee. A 2.5 L AMC 150 Inline-4 motor was available on entry-level models until 2003 when the 2.4 L DOHC Neon 4-cylinder engine replaced it.

All Wranglers have part-time four-wheel-drive systems with two-speed transfer cases. This, plus the short overall length and minimal overhangs, gives the Wrangler an almost unstoppable nature off-road, but provides a somewhat bouncy ride on anything but smooth pavement. Axles on a standard Wrangler are Dana 35s, with a 3.07:1 ratio; the tall gearing works against the four-cylinder and the TJ's barn-door aerodynamics on the highway. The axle option is the locking Dana 44 with a 3.55:1 axle ratio, which promises better acceleration and off-road capability in four-low. (The '03 Rubicon model offers a pair of these locking axles as standard equipment, along with upgraded suspension.)

The TJ have saveral trims i.e: Base SE (2.5-liter, 120-hp inline-4), Sport (4.0-liter, 190-hp inline-6, fancy wheels and graphics) and Sahara (4.0-liter six, air-conditioning, upgraded upholstery, CD player) trims were offered initially. By 2003, the Wrangler "X" (slotted above the SE and featuring the inline-6) and "Rubicon" (featuring hard-core off-road stuff such as a super-low range in the transfer case, 31-inch tires and locking Dana axles front and rear) trims debuted. Transmission choices included a five-speed manual and three-speed automatic, the latter upgraded to a four-speed unit for 2003. The new-for-'03 2.4-liter DOHC four sourced from the Liberty SUV adds 27 horsepower compare to the previously 2.5 inline-4. This 2.4 liter engine is quite enough for hauling TJ body especially for city and light offroad driving.

In 2004, Jeep introduced the Wrangler Unlimited model; it still had only two doors, but a 10-inch wheelbase stretch provided a significant increase in rear legroom and cargo capacity. A Rubicon version of the Unlimited arrived the following year, and a six-speed manual gearbox replaced the five-speed.

The engines are nearly bullet proof, especially the 4 liters inline-6. The 4.0-liter throttle-body butterfly needs to be kept clean, as coking up will cause an air leak at idle--watch for fluttering idle speed, however if you regularly maintain the engine, there is almost no problem with the engine. My 1998 TJ has almost 100,000 miles on the odo, without any major problem with the engine. A typical service interval between tunes and fluid changes is 24,000-30,000 miles. Those manual transmissions should be serviced at 30,000-mile intervals in normal usage, more often if used heavily off-road. You should put more attention in the hoses, either power steering hose, automatic transmission cooler hose or engine cooling sytem hoses. By age, this rubber hosses start to torn, or leaking. Leaking in transmission oil cooler hoses can damage your entire automatic transmission system.

The Jeep Wrangler for its off-road agility and personality is superb but scorned the plastic side windows and fussy soft top. This TJ is good for commuter duty, considering the vehicle's loud and busy ride at freeway speeds. Gas mileage as always become a main issue in Jeep was mediocre, slightly better than Grand Cherokee, its about 1 liters for 6 km in the city and 1 liters for 8 to 9 km in freeway. The standard, non-Rubicon version of the Wrangler Unlimited had slightly better road manners, thanks to its longer wheelbase and revised suspension tuning. However the Rubicon version which is superb in off-road capability but simply too harsh and bouncy on the blacktop.

When you buy a TJ a bunch of accessories are waiting to follow, there are plenty and almost unlimited choice. However suspension modification and lifting the TJ should be done properly, otherwise a typical jeep problems like death wobble, unbalance drive shaft, cv joint damaged can occur any time. And the last, ...be ready, every eyes will following you, .......Wrangler TJ is so sexy.

See my other post about wrangler jeep in Cars and Bikes blog

BUYING USED: GRAND CHEROKEE WJ

The WJ Grand Cherokee released first time at 1999. WJs, which were virtually same as WGs, were of slightly unusual design. It’s coming with more rounded shape compare to its predecessor Grand Cherokee ZJ/ZG. They featured monocoque chassis in order to increase interior space and remain car-like but used live axles front and rear. This was done to maximize off road ability over an independent suspension.

Grand Cherokee earned the nickname “Wobbly Jeeps” because they A-frame rear, top suspension link, which over superb axle articulation, doesn’t locate the rear axle as well as other means, making the car wobble.

These models were fulltime 4WD and came with the option of Quadra Drive II 4WD traction system, which provide limited locking of the front and rear diffs. While the system worked well, it was no match for diff locks, so if you are buying a Grand for hard off-road use, avoid the Quadra Drive equipped version, as it’s hard to convert them to run lockers.

Because of their monocoque chassis and very short front and rear trailing arms, WJ/WGs don’t lend themshelves to extreme off-road modifications. These models benefit from simple mods like fitting swaybar disconnects, a 2 in lift and diff locks, which combine to make the Grand a pretty capable playmate.

Again, if you want a 4WD to use for hard core off-roading, it’s best to look elsewhere. While they have been modified to performed off road miracles, be prepared to fork out plenty to achieve this end. Aftermarket products are limited compared to TJ, XJ and ZJ, especially if you are living outside of US, even bullbars are only sold by few suppliers.

BUYING USED
Being luxury vehicles, and priced accordingly when new, most WJ/WGs were purchased by older, more sedate owners and were seldom modified. This means there are plenty of good examples floating about that haven’t set foot off-road.

Because of the complexity of these vehicles and their quirky faults, it is always advisable to take any prospective buys to a Jeep specialist for once-over. To help you choose a vehicle worthy of a second opinion, follow this step:

- Walk around the vehicle and take a long look at the body work in good daylight, checking for paint inconsistencies and misaligned panel gaps that indicates the Jeep after a crash.
- Open the doors and check that the woodgrain trim inserts aren’t starting to fall off. Check the electric front seat adjuster, as well as heated seat work, which are prone to failing.
- Inspect the CV joint in the front propshaft, this joint breaks without much effort when off roading. Some manufactures offer a uni-joint replacement kit, which prevents this happening again.

- Check of visual signs on both the front and real trailing arms. The Grand Cherokee’s unsusual oval-shaped bushes wear out by about 100,000 km. This is partly due to the very short trailing-arm length and bush design.
- Check the outer front axle seals aren’t leaking this will be evident by oil around this area

- Looks for leaks around the transfer-case output shaft seal.

- Inspect leaks from the inspection cover gasket on the front and rear diffs.
- Under the hood, first check for coolant leaks from the radiator, the leaks occur commonly between the aluminium radiator core and the plastic side tanks. It is very important that there are no coolant leaks, because if the V8 engine overheats, and plenty of them have been known to, the alloy heads expand and cause the steel valve seats to fall out, causing major and expensive engine damage.

4x4 Parts and Accessories Links

My favorite links for 4x4 parts and accessories are listed below:

• WARN : winch, body armor, axle, lighting system, bumpers and mounting system, etc.
• 4WD : Jeep Parts and Jeep Accessories – Low Prices and Fast Shipping – Jeep Parts and Jeep Accessories.
• ARB : Australian 4WD vehicle accessories manufactures. Bull bar, body armor, IPF light etc.
• QUADRATEC : Jeep Accessories at Quadratec. Specializing in Jeep Wrangler, Jeep Cherokee, Jeep Rubicon and off road Jeep parts.
• CALMINI : manufacturer of quality Suzuki, Isuzu and Nissan suspensions systems, lift kits and 4x4 performance products.
• SKYJACKER : suspension, lifting kit etc.

PETROL VS DIESEL ENGINE

When choosing the 4 WD vehicles, the engine type is one of the most important to decide first. There are three things to consider in choosing the engine:
1. Petrol or Diesel engine?
2. Engine capacity and engine output (in this case are power and torque).
3. Where do you live, is in country with good quality fuel or in the country that most of the fuel are contaminated.
4. What the main use of your 4WD, long distance trip? Camping? Soft off-roader? Hard off-roader, rock crawling? City slicker?

The ideal powerplant for an off-roader is able to produce its power at low RPM. Engines that do this can be driven in higher gear ratios in difficult terrain which is advantageous because the higher the gear ratio, the less chance of wheel-spin and the more delicately the driver can control the engine’s power output. Engines designed with long piston strokes tend to do this.

Good off-road driving technique calls for selecting the right gear for the conditions. If the gear ratio selected is too high, a more powerful engine may still have the torque to get through, but if the gear selected is too low, a big engine could, if not handled skilfully, cause excessive wheel-spin and bogging down. For a novice driver therefore, high power is often a disadvantage. For long distance travel, larger engines are more reliable than small ones because they rev slower – but the penalty comes in higher fuel consumption.

FRONT SUSPENSION COMPONENTS (JEEP)

There are some parts that always become a discussion among the four wheelers, one of them is front suspension parts. The sketch below is a typical front suspension of 4WD LHD Jeep (CJ, YJ, TJ, XJ and ZJ), lets get familiar with the termination.




1. Stabilizer Links
2. Shock Absorber
3. Upper Suspension Arm
4. Stabilizer Bar
5. Coil spring
6. Jounce Bumper / Bump Stop
7. Lower Suspension Arm
8. Track Bar
9. Axle and Differential
10. Steering Stabilizer
11. Drag Link
12. Tie Rod
13. Cross Member

DEATH WOBBLE

Since I have quiet a lot of experienced dealing with death wooble in my cherokee and grand cherokee jeep, I will post several articles for this subject including my own experience. The next article wrote by Nathaniel Long three years ago, its can use as basic reference for death wobble.

If you drive a Jeep Cherokee or Grand Cherokee and are considering a suspension lift, you may want to think twice. Unfortunately, I was forced to learn this the hard way. I bought a brand new 2001 Jeep Cherokee a couple years ago, and almost immediately stacked on Pro Comp’s 3” lift kit with some 32 x 11.50 r 15 Super Swamper TSL tires. After a couple months of good riding, I started to experience what jeep enthusiasts have come to know as “the death wobble.”

The death wobble is basically when you are driving your lifted jeep down the road and the front end starts to shake violently. It can happen at virtually any speed, though mostly above 40 mph or so, and is a frightening experience, especially for those witnessing it for the first time. Now it doesn’t throw you off the road or anything … the front end just shakes. And the only way to stop it is to slow down and pull over. So it wasn’t that hard to get used to at first. But as it happened more and more, it seemed to get more and more out of control.

After driving with at least one death wobble per day for about three months, I decided to take it into the shop and see what the problem was. Being of course that off-road shops are primarily in the business of ripping people off, they gave me a list of “everything that was wrong with the front end that is causing the ‘TJ shimmy.’” Their proposal included the rotation and balancing of my tires, new front (and rear “cause you might as well”) shocks, new and stronger track bar, new and stronger drop pitman arm, new and stronger lower control arms with some special urethane bushings, and new sway bar links. Basically, with the exception of my original lift springs, the reinstallation of the entire Pro Comp lift kit with “better” components.

The bill was just over $1000.00. But to fix my death wobble, and hence my daily fear for my life, it was worth it. And even better, the new components would be strong enough to support a 6” lift if I ever wanted to go that big. The words of the salesman still ring in my ears: “Dude, you could totally run 35s with this setup.”

For the next couple months, everything ran fine again and I just assumed that my former Pro Comp parts just sucked. I even took the kid’s advice and jumped up to 33 x 12.50 r 15 tires. My new components were working brilliantly. Then one day, riding down I-70 toward the mountains, I hit a pothole and back came the death wobble. For the next couple months, I experienced the death wobble every time I hit a pothole, crack, or even merged onto a simple uneven lane.

Back at the shop, the guys, obviously not recognizing me from six months before, gave me the same proposal as the first time … almost word for word, too. My shocks, track bar, pitman arm and control arms were all shot again and needed replaced with their “better and stronger components.” The guys didn’t even take the time to see if my components were the same ones they had sitting on the shelf. In fact, the parts they wanted to give me this time were likely the same Pro Comp components they had replaced initially. At this point, I realized that I’d have to take matters into my own hands.

I had a buddy sit in the driver’s seat of my jeep and shake the steering wheel back and forth in an attempt to recreate the death wobble so I could view it from the other side. After not even two minutes, it became clear to me what the problem was. All my components were fine. The shaking was coming from the frame rail, which is connected to the axle.

What was happening was simple: My tires, as off road tires tend to do, kept going out of balance. Therefore, when I hit a pothole or uneven pavement, or too high a road speed, the tires would start to wobble and fight back and forth against each other. This is probably how Fred Flintstone felt driving around with those rock tires. The fighting tires would cause the axle to shake back and forth, which in turn caused the frame rail to shake. Hence the death wobble. Now the wobble could have been stabilized by the bar attached to the frame rail; if only it was attached to a real frame.

See, Jeep Cherokees and Grand Cherokees have what is referred to as a unibody design. This means that they don’t have frames like a real vehicle, just a combination between a frame and a body. It’s kind of like a tin can on wheels. And if you put tires under that tin can that are too big and heavy for it to handle, it’s going to shake all over the road.

Now I’m not saying don’t lift your Cherokee, I’m just saying don’t lift your Cherokee too high. It can handle 31s or 32s, but if you get any bigger or heavier tires, it won’t be strong enough to consistently support them. If you want to lift a Jeep vehicle for off road purposes, I’d recommend a Wrangler. It has a frame, meaning it can handle big and heavy tires, not to mention a roll over.

If you’ve already got a Jeep Cherokee and are experiencing death wobble, don’t listen to the guys at the shop. They’re just trying to get your money! Test each of the components of your front end yourself. Most of them are rock solid and rarely need replacement. Instead, just get your tires balanced. It should fix the problem right away, at least until the tires go out of balance again. To end it permanently, unless you can somehow fabricate a stabilizer bar to strengthen the front-end frame rail, the only thing you can really do is switch down to smaller tires. Or buy a normal road car …

BUYING USED: GRAND CHEROKEE ZJ

History
The Jeep Grand Cherokee is a midsize SUV made by Jeep, a division of Daimler-Chrysler. The Grand Cherokee was a spinoff of the notably smaller Jeep Cherokee. The ZJ models, manufactured from 1993 to 1998, originally came in 3 general trims, the Base, Laredo, and the Limited. The Base model (also known as SE) offered basic features such as full instruments, cloth interior, and a five-speed manual transmission; The SE model was dropped in 1996 in favor of the Laredo. The Laredo is the mid-scale model, features included added body cladding, fancier seats, power windows, power door locks, and cruise control; exterior features display a medium grey plastic lower body paneling and five star spoke aluminum wheels. The Limited is the premium model, with the lower body paneling being the same color as the vehicle color. The Limited also boasts features such as leather seating, optional power sunroof, mirrors, seats, and remote keyless entry system; a basic onboard computer; and waffle-like cast aluminum wheels.

In 1996 some cosmetic changes ranging from improved body modeling (grille, bumpers), better wind aerodynamics, and integrated fog lights; Interior features added dual-airbags and increased fabric quality for seating. At the same time, the American Motors-fonted "Grand Cherokee" fender emblems were replaced with a font style used on other Chrysler vehicles (e.g. Sebring, Breeze). The AMC 4.0 L I6 engine was also refined, though receiving slightly less horsepower (185hp) but gained more torque and presented quieter operation. Limited models that year and on had more luxury items such as driver placement memory, remote radio control from the steering wheel, and variable assist while driving and parking. A sporty TSi model (1997-1998) briefly debuted, exterior features included single color body paneling, with a light blue striping accent. TSi packages came equipped with 16-inch alloy wheels, 225/70R16 tires, leather seats and premium sound system. The 5.9 Limited was produced only for the 1998 model year, having more luxury than that of the regular Limited. It housed a powerful 5.9 L V8 engine with an output of 245 hp and 345 foot-pounds of torque, going from zero to 60 mph in only 7.3 seconds, making it the quickest SUV available that year. Other features separated the 5.9 from the standard Limited model, such as mesh grille insert, unique five-spoke alloy wheels, improved premium stereo, and softer leather trim.

4WD systems included Command-Trac, a part-time unit offering temporary 4-wheel assistance; Command-Trac was dropped from lineup in conjunction with the SE trim in 1996. Select-Trac had the option of either full-time or part-time operation; Both shift-on-the-fly Command-Trac and Select-Trac were already available for the Cherokee XJ lineup, and were adopted to the ZJ platform. Exclusive to the Grand Cherokee was the introduction of Quadra-Trac having all-time four-wheel assistance only, this was standard on all Limited and specialty trims and optional for Laredo models alike. Two-wheel-drive models were sold though only for "Laredo" trims in late 1993, it wasn't until 1994 when 2WD was available for Limited; and in 1997 5.2 L V8 engines were sold along with 2WD.

What to Check and Inspect
For general check please read my previous post in this blog. After general check at exterior and interior, lets go more detail for ZJ inspection:

ZJ Interior:
- check the driver side power window control panel, makes sure all power window are works. This power window control is easy to be failed caused of electrical problem. To fix it is pretty easy, normally the mechanic add on/off switch between the fuse and the power window control. If the control failed, simply disconnect the electric current for a while and reconnect again, usually the PW will work normally again.
- Check the steering wheel cover quality, most of them easily to torn, its minor problems but you will facing it for every time you drive this ZJ
- Inspect the spare tire location on the rear cabin, make sure all the tire lock parts still in there, if the ZJ used 31” tire, the hanger must be have been modified, caused its design for 29” spare tire.
- If the ZJ equipped with electric seat, try to operate it.

Under the Body:
- inspect the CV boots, if it already torn, look at inside the boot, if you find some grease still in there it might be ok, but if you find a dirt or sand, its better to look at for another ZJ.
- Check the CV boot and joint at front drive shaft (this is for 97-98 ZJ), this part is easy to damage especially if the Jeep have been lifted more than 2” without modification on its drive shaft. The older ZJ used U-joint and slip yoke same as the one installed in XJ Cherokee.

- Inspect for transfer case seal leaking, its not a major problem, however you should replace the seal as soon as you buy the car.
- Check the exhaust system, the catalytic converter, muffler and also fuel tank. A poorly dent, bent and scratch in this area indicated an abuse using while off roading by the previous owner.
- If the ZJ have been lifted, make sure its installed properly, including proper wheel alignment. Death Wobble is common in this ZJ.
- I’m not recommended to buy a ZJ which have lifted more than 2”.

Under the Hood
- As mention in my other post, the AMC i6 engine is really a bullet proof, not many problems with it. Just check for the fluid, especially the coolant, make sure there is not oil trace in there.
- Pick the auto transmission oil dip stick, check the quality and the quantity. If still red and not dirty, it will be fine. Check also the volume. Note to check the auto transmission fluid level, the engine should be running and move the gear stick to “N”.
- Inspect the electronic fan, this one is proven to broke easily.
- Check for any leak from hoses, especially the for high pressure hose from automatic transmission and power steering.

Test Drive
- Turn on the engine, move the gear from P to R or D, do not press the throttle, let the gear engage than slowly pulling the car. If there is any delay, it is a poor auto transmission indicator, find another ZJ. Try also the 2 and 1 gear.
- Drive the car slowly and if possible go to dirty road or drive along side of the road, listen for any strange sound coming from the front and rear suspension. Any “dug” or ‘clunk” sound is indicator of poor tie rod and stabilizer link condition.
- Drive the car constantly at 35-40 mph, listen for any noise coming from lower part. The latest product of ZJ (1997-1998) are using “low-pinion” or normal-cut pinion for its front final gear (Dana 30). This type is less strong than the “high pinion” which is installed in the previous product, and lot of reports mention the damaged of front ring and pinion in very low mileage ZJ (mine was change at 9000 miles).
- Body roll is quite excessive in ZJ, its normal, you can install a harder spring and shock later on.

More articles on ZJ jeep can be found in this site and this site

BUYING USED 4X4 VEHICLES

Buying used used 4x4 its fun and a bit tricky. Usually the person who have a plan to buy used 4x4 have also another plan in their mind: go to 4WD shop and looking for some additional accessories for the their 4WD.

Before you buy, take a little time for internet research, talk with your friend who have 4WD, then its good if you can decide what type 4WD that you want to buy. In this case its often someone want to buy a Jeep in their mind and back home with a Nissan Patrol.

If you serious about modification plan, consider your geographic area. In United States of course is a heaven for Jeep or Ford owners. In Aussie, jeep is minority and lack of available accessories, however its bunch and plenty supporting equipment for Toyota and Nissan. In Europe maybe you can looking for Land Rover.

There are some tips before you decide to purchase:
- Do a quick inspection for the exterior, looking for body damage, rust or maybe poor roof condition. Small dent and scratch is normal.
- Try to open and close all doors, make sure all doors can close properly. A poor door alignment is a sign that vehicle has a major crash previously.
- Open the engine hood, looks for any leaking from the engine, check for torn wire, check the fluids quality (engine oil, trans oil, brake oil, power steering oil).
- Check the radiator coolant, make sure there is no oil sign in the coolant.
- Go inside the car and inspect the interior, especially in the floor area. If the previous owner used this car for real off roading, there is always potential they used this car crossing a pond or river. A water could trap under the carpet and starting rust. Check all electrical instruments including air conditioning function.
- Turn on the engine, let it idle for a while. Inspect for any strange noise from the engine. If you look at for diesel engine 4WD, took a close hear near the injector pump. This pump is one of the main consideration, it is costly to repair.
-Engage the gear, and ask for test drive. If you inspect an automatic transmission car push the gear lever to every position (P, N, D, 3, 2, 1 etc), feel the engine pulling before you push the throttle.

That the above tips actually can use for any car, not only for for 4 WD. For the 4WD car you might need to inspect more like:

-After you check the gear in any position, then you should check the main 4WD facilities, the transfer case. In conventional 4WD is always using the second and smaller trans selection stick. In certain jeep there are 2H, N, 4H and 4L position. Try it all, if you are a beginner, ask the seller how to move the lever. Do it firmly without stop. Some times a “creeek” sound occur if you not move the lever firmly, its ok. After the selection engage try to move the car, make sure the gear still in its position, not pop to normal. The selection of transfer case position is vary from car to car. Some 4WD cars have no TC gear stick, the TC mode select by pushing a button. Do the same above procedure for push button 4WD like this.
- Now is time to crawling under the vehicle. Note: make sure the vehicle in save position. First check for oil leaking, its can be come from the engine, transmission, transfer case, front and rear axle, and sometimes come front high pressure hose for power steering or oil cooler. Minor leaking is not a major problem as long as the oil is always in the required volume.
- Go to front suspension system, this is the most complicated part to be inspect in 4WD vehicles. Check for the coil spring and shock absorber condition. Inspect for CV joint boot, this boot is easy to torn during off road driving.
- Check any scratch and dent, the muffler and catalytic converter is easy to dent, and the fuel tank is easy to scratch. Both indicators showing an extensive off road use.
- Look at tie rod and drag link boot, both parts are good indicator of maintenance frequency: degenerated boots and lube boggers show a great lack thereof.
- Gripped the driveshaft and rotated it side to side to check U-joint play in the yokes. It’s also a good idea to take a look at the U-joint straps or bolts to make sure that you won’t drop a driveshaft on the way home.
If you looking at RHD XJ Cherokee, inspect the steering rack – body connection, is. This steering rack house is proved to broke easily, reinforcement is mandatory.
- If the vehicle is equipped with suspension lift more than 1.5” , make sure it has all of the necessary equipment, such as transfer case drop-down or slip-yoke eliminator/short shaft kit and extended brake lines.
- Back to under engine hood, check the alternator, most of 4WD equipped with charge level meter, makes sure the charging level between 13-14 volt.

Additional bonus to consider: winch, after market front bumper, additional light, suspension lift kit, dual batteries system, differential lock, >31” Mud Terrain tyre. That equipment is not cheap, so is a big bonus if theseller already equipped their car with those things. However you should check that all of that equipment are properly install