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2002 Jeep TJ & 1978 Jeep CJ-5 - Your Jeep

Posted in How To on June 1, 2007
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Loading The LockersI am about to change the gearing in my Jeep to 4.56 from the factory 3.73 and want to upgrade to a locker in the back and a Detroit Truetrac in the front.

I have read a little about the TJs having some funny quirks on the road with an automatic locker, but no real details. Most of my friends' Jeeps only get driven from the trailer to the trail and never go very far on the highway. They think the Detroit Locker is the holy grail of lockers and are pushing me to get one, but only about 30-50 percent of my time is spent off-road. I don't know anyone that is running an automatic locker in the back of a road-driven TJ.

Could I get your opinion on the following rear differentials for this '02 TJ with a Dana 30 front, Dana 44 rear, and a 4-inch short-arm lift with 33s: Detroit Locker, Detroit Electrac, and Detroit Trutrac in the back (I know they are good on the road, but what about off-road?).Mark Hillis Via e-mail

I absolutely love the Detroit Locker, but I'd never put one in the rear of any mostly short-wheelbase rig I own for street use.

A 4-inch short-arm kit is going to accentuate the negative handling characteristics of the auto locker in the rear of your Jeep. When you're under power (on the gas) in either Forward or Reverse, the Detroit will be locked up just like a spool. When you get off the gas (or coast or even when the drivetrain isn't under load like coming to part throttle after being at full or three-quarter throttle), the locker will unlock. It often does so rapidly. This locking and unlocking in the rear axle isn't as noticeable in a straight line, but when turning, it can cause some handling issues, especially if you're not running sway bars or if you have soft shocks and springs.

I think you'll get used to the handling quirks, but you really won't be able to toss your keys to any driver inexperienced in operating highly modified vehicles. The Detroit Locker even comes with a warning sticker that says your vehicle is going to handle differently.

If you're wheeling off-road 30-50 percent of the time, I'd say you need a locker (not a limited-slip) in the back of your Jeep. The Detroit Electrac we put in the rear of our '00 Wrangler, Red, blew up after some hard use; they're just not highly durable pieces. I've had good results with ARB Lockers, the TeraFlex T-Locker, and the OX Locker. If I could state my case for the OX, there are no seals to wear out, you don't need a compressor, and it's 100 percent mechanical. The drawbacks are that the installer needs to adjust the cable correctly or it won't shift right, and you'll need to route the heavy cable into the interior and find a place to mount the little shifter. Do some research and any one of these should give you the performance you're looking for with no adverse effects on-road.

Fuelin' Foolin'I have a '78 CJ-5 with the 258. It's all stock, aside from some headers that came on it. I recently had a remanufactured, single-barrel carburetor put on to replace the bad factory one. To say the least, I hate it! I wanted a Weber, but my wallet said otherwise. Anyway, I have a heck of a time starting her up when she's cold. Pumping and feathering the gas and trying to turn it over numerous times to keep it running is getting old. Then I have the manual choke to deal with.

When I finally do get it started, it spits and sputters for a good while. I also have black spots from the exhaust in the driveway where it idles, and there's the strong gas smell. I'm constantly playing with the choke to get it to accelerate right while I'm driving. In fact, it seems to drive better at times with the choke on rather than almost flooding out/bogging down with it wide open. Sometimes, when I turn the engine off, it continues to run for a brief second then a hiss is heard-kind of like a pressure release before it quits. What can I do to get it to start and drive normally without getting crazy expensive?

I'd also really like to axe the carb and go with fuel-injection. I thought I read somewhere that TBI from a Chevy would work. Is this true? If so, how difficult would it be to do? What exactly would I need to look for in a junkyard? Are there any other parts I would need to purchase for this?

Thinking long-term, I would like to rebuild a Jeep from top to bottom. I figure by the time my 16-month-old son turns 16, I should be about done with it (ha ha). For me, there are way too many options out there. If possible, I'd like your expert opinions when it comes to selecting what I guess you could call the four main items: engine, tranny, T-case, and axles. For the engine, do I build up the inline-six, go V-6, or even V-8? I've been reading about a head from Hesco and Avenger Superchargers. What are the pros and cons of building a six versus an eight? My tranny right now is the T150 three-speed. It definitely doesn't cut it for a daily driver at 50-60 mph. I've thought about the T-18 (the 700R4 also seems pretty ideal to me). I was also just reading about the NV4500 or NV3550 the other day, as well. Will a 700R4 mate with an inline-six? As far as transfer cases, although pricey, it seems like the Atlas II is the weapon of choice. The Dana 300 also sounds promising. I'm not too sure about the others, such as the NP205, NP231, and so on.

Then there are the axles: Dana 44, Dana 60, and Ford 8.8- and 9-inch. What does it all mean, and how is one better than the other? Does it have to do with length and width? What about the different types of lockers, such as electric, pneumatic, and so on?

I'd say that 85-90 percent of my driving is on the road to and from work. I'd like a well-rounded Jeep for muddin', trails, huntin', and daily driving.Brent M. ShieldsSSgt., USAFIYA Ammo YAS

Man, That's A Lot In One Letter.First, Webers are OK, but they're not much better than the Motorcraft 2100 2-bbl carbs that can be found on just about any '70s or '80s Ford six- or eight-cylinder in the junkyard for $20. If needed, add a $15 rebuild kit from Napa (pretty easy to install), and you're in business. There are a few different versions, and the way to tell is to measure the venturis. For a six-cylinder, you want the one with 1.08-inch venturies. Some of them have the venturi size stamped into the housing-sometimes behind the accelerator-pump linkage. The easiest way to nab the correct one is to just make sure the carb you buy is off of a six-cylinder. Trans-Dapt ( has the carb adapter you need to mate the large-bolt-pattern Motorcraft carb to your small-pattern manifold under PN 2086.

Second, a TBI conversion can get pretty expensive and complicated unless you've got a donor vehicle sitting there in your driveway. Don't forget you'll need to install an electric fuel pump, all the sensors, wiring harness, and so on. When it's all said and done, the 2-bbl Motorcraft is a whole lot easier and will surprise you with its off-road performance at angles if you lower the floats a little.

Third, a V-8 swap is just more reliable and sometimes a little easier than trying to put 4.0L parts on a 258. If your personal preference is the TH700R4 over a manual, then that's your decision, but the NV3550 is a darn fine transmission for the moderate Jeep owner who only wants 33s or even 35s. You can mate a TH700R4 to the 258; call Advance Adapters ( and order a catalog or browse Novak's Web site ( If it were my Jeep, I'd consider a few options:1) Rebuild the stock 258 with Motorcraft carb, mild cam, good ignition, T-18, stock Dana 20 T-case with 32-spline rear output shaft, 4.10 gears, alloy shafts in the Dana 30 front, and one-piece shafts in the Model 20 rear. This would be pretty cheap and easy to accomplish and would really support the use of 33-inch tires. Plus, you'd be using parts you already have (with the exception of the transmission), and the buildup could take place as funds permit.

2) Chevy 305 or mild 350 V-8 with factory Q-jet carb, TH700R4 tranny with Novak or Advance Adapter T-case adapter, Dana 300 T-case with 32-spline rear-output shaft, 4.56 gears, Dana 30 front with alloy shafts, Ford 9-inch, or Dana 44 rear axle. Again, this would be good with the use of 33s and would have great power,off-road driveability, and would probably knock down 18 mpg with the 305 engine.

3) Painless Wiring is currently working on a complete 4.0L Jeep harness with a Delphi MEFI 4 computer to control it. Basically, this would allow you to grab a junkyard engine with all the injection and sensors and just plug in the harness and computer and go-no worrying about complicated factory wiring harnesses or computers. It should be available within the year and will most likely go for around $1,000-$1,500. Expensive, but it makes for a pretty easy injection swap. Add a Bosch or Ford external fuel pump near your factory fuel tank, and you're set for an injected 4.0L. I'd nab the engine from a '91-and-later XJ, YJ, or TJ as well as an NV3550 transmission and add a Dana 300 T-case with a 32-spline output shaft. Run 4.56 gears, Dana 30 front with alloy shafts, and either the stock Model 20 with one-piece shafts or a Dana 44 rear out of an '86 CJ. This would give your early CJ the performance of a new 4.0L Jeep, but then you may just want to step into a 4.0L YJ or TJ.

Cool ToolCan you direct to me where I can find that driveline tool for removing U-joints that you demonstrated a few years back?JohnVia e-mail

I own a Harbor Freight Tools( four-wheel-drive, ball-joint service tool (PN 4065-OVGA). They go for about $60 and are really handy for pressing ball joints, but I've only used it to do U-joints once. It's just quicker and easier to use a couple of sockets, a hammer, and a bench vise.

Got a tech question you're just itching to get answered? Send it on in to Jp Magazine, Your Jeep, 6420 Wilshire Blvd., Los Angeles, CA 90048, or e-mail

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