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November 2009 Your Jeep

Posted in How To on November 1, 2009
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Factory Locker?
I have a '97 Wrangler Sahara TJ. This is a completely stock Jeep except for the tires, which are 30s. Whenever I stomp on the gas both tires turn on the rear end. I thought maybe the previous owner installed a locker, but there are no outward signs. There aren't any lines from the rear housing or switches anywhere to be found. So I thought I was just crazy until another Jeeper was following me on a trail and asked why I had my locker on while on this very minor trail. What's going on?

We put it on the rack and turned the drive shaft and both tires turned. I couldn't figure it out until I read an article in Jp on lockers. That is when you mentioned "auto lockers." Did this Jeep come stock with one? We popped the rear cover off. (I had 200K on the clock, so it needed new oil anyway.) I then realized I had no clue what I was looking at. It doesn't matter if I'm on the street or trail; if I step on the gas I get two smoking tires. What do I have? Limited slip? Auto locker? Or is my wife right in stating I am just obsessed on rear ends? Any help or medication would really help.
Vann Campbell
Republic of Tejas.

Don't take it too hard, but you have no future as a magazine photographer! I couldn't tell exactly what diff you have from the photos you sent because they were too blurry, but based on what I could make out I'm certain you don't have a locker.

Most likely your Jeep has a Trac-Loc limited slip. It's a relatively low-torque bias limited slip made by Dana/Spicer and was offered on many Jeep Wrangler YJ, TJ, and Cherokee XJ models with the six-cylinder. If you spray a little brake cleaner on the differential case on the side the ring gear bolts are on you'll probably be able to make out the words "Trac-Loc" and "Dana Spicer" somewhere. You can also look inside and try to see behind the spider gears (the ones on the side of the case where the axle shafts go in). You'll see a recessed bore and two little metal clips holding what looks like a stack of washers behind each side gear. These are your friction plates.

While it's not uncommon for Wranglers to have a limited slip from the factory, it is uncommon for them to still work that well after that many miles. A lot of it can probably be attributed to your small tire size. Just make sure when you refill the diff you use gear lube with a friction modifier in it. Most lubes sold at autoparts stores already have this modifier. It'll say something like "for use with hypoid/limited slip differentials." Or, you can visit your local Jeep or Dodge dealership and buy a little 4-ounce bottle of friction modifier, PN 4318060 and add it to your oil if you've already filled it with plain 90W. Without the friction modifier the limited slip will chatter and wear the clutches prematurely.

Young Jeep Lust
My 16-year old son is a new subscriber to your magazine and is convinced that he can do what you did with your cheap $500 '89 Wrangler. To that end he has narrowed his search and pulled all of the money he has, convinced me to rent a trailer, and tomorrow we leave to tour two Jeeps, of which he seems convinced one is coming home with him.

His choices are between a '53 CJ-3B that runs but needs help: ultimately a new tub, new wiring, and brakes. Or, a '66 CJ-5 with a replacement fiberglass tub that is in running order with the exception of needing the gas tank replaced. And the '66 comes with a snow plow.

He had previously settled on getting the '53, but got a call out of the blue about the '66 being available. He wants to use them for occasional travel to school, as well as some off-roading.

Both are in the $2,000 range. Neither has tops and he plans to work his summer away on the choice of the two. We look at the CJ-5 first tomorrow. I am not a mechanic, expert or such but know enough to make repairs and curse my way through a repair manual. I ran across his latest issue of Jp on my way out of the house this morning and thought if there is any advice you can give with the little info I've provided, it would be a huge help.
Todd Freeman
Newark, Deleware

I'm not sure if you're writing in hopes I'll talk him out of it or not, but in my opinion the CJ-3B is way not worth $2,000 if it needs all you say it does. Sounds more like a $500 project to me. Low ball the owner and walk if he doesn't accept.

As for the 'glass '66, beware of electrical gremlins and make sure the body was properly mounted to the frame. There's a lot that can go wrong with a fiberglass rebody and few take all the precautions necessary to ensure the wiring will have proper grounds, seatbelt anchors will be safe, etc. Aside from that, the frame will still be a '66, so look for cracks and rust holes, check the steering (should be the old Ross cam and lever setup, unless it was converted to Saginaw), and the axles will be runty Dana 44 rear with 19-spline, two-piece shafts and the front will be a Dana 27 with drum brakes. Not the best material for a daily driver or trail buildup.

If I can offer any real help it would be to suggest your son show some patience and wait for the right deal to come along. It's easy to read about how I nab a Jeep in great shape for $500 and get it running and wheeling for less than $1,100, but the reality is that I waited nearly three months for that deal to come along. And that was three months of searching the internet like a fiend several times a day, every day. I'd also recommend he look into a four-cylinder Wrangler like I bought, as you get more for your money compared with an early Jeep. Unlike the older CJs, the Wrangler body tubs are galvanized for corrosion, the wiring and frames are better, and any four-cylinder Wrangler will have factory fuel-injection.

Stay off of eBay and check as a good means to search more than one geographic area of craigslist at a time.

Under Pressure
We just picked up a '94 ZJ and want to know if the rear discs will fit on our '89 XJ's Dana 35 since the ZJ also has a 35.

Also, on our '89 XJ, it keeps popping back through the throttle body. We have replaced everything we can think of and it is still doing it. We have checked the throttle, air, EGR, distributor, plugs, wires, and the crank sensor. It is still doing it and I'm at a total loss. Ray Travis
Barton, New York

The '89 XJ has a non-C-clip Dana 35 rear axle. The '94 ZJ is a C-clip Dana 35 and has a different backing plate bolt pattern than the non-C-clip Dana 35s made up until '90. Short answer, they won't fit.

As for the popping through the throttle body, check for a vacuum leak in the miles of plastic lines and around the manifold intake. With the engine running, spray throttle body cleaner around the gasket surfaces of the intake and around the vacuum line connectors. If the engine rpm increases, you've found a leak. Trasborg also suggests checking the vacuum canister and lines located underneath the battery box.

If no leaks, I'd check the fuel pressure with a gauge while the engine is running. Low fuel pressure will cause it to pop as you describe. You should have at least 29psi fuel pressure with the vacuum line connected to the fuel pressure regulator and at least 39psi with the vacuum line disconnected. If not, your pump or fuel pressure regulator may be the culprit.

I'd also check the cam position sensor in the bottom of the distributor and the catalytic converter.

XJ Chop Shop
I have a '91 Cherokee Laredo and my suspension has had it. The Jeep is all stock and I would like some advice on how best to convert this XJ to an awesome off-road beast for cheap.

I also have a '96 Cherokee Country and if you know what is transferable between the two that I may use to my advantage that may be helpful. The '91 has reached the point where everything is starting to really need replacing.
Chris Norbert
Anchorage, Alaska

Pretty much everything will interchange between the '91 and '96 as long as they're the same drivetrain (4.0L, AW4 overdrive auto, T-case, etc). If you go swapping axles, plan on checking the gear ratio to make sure they're the same between vehicles if you're only going to replace one axle assembly.

Put a CJ clip on the YJ, weld the turn signal holes up, and put TJ turn signals and flares on it. If you wanna go all out, put the TJ footman loop, windshield bumpers, and latches on it too. Way easier and basically gets you the same look.

The biggest difference between the two vehicles is in the engine management systems. The '91 is the simpler OBDI, while the '96 is the more intrusive OBDII. The OBDII makes it more difficult to tune if you're doing major engine modifications like a stroker kit, turbocharger, and so on. However, the '96 should respond well to simple bolt-on upgrades like a header, after-cat exhaust, and cold-air intake.

As for the tires and suspension, shoot for 33s or a maximum of 35s. To accomplish either you're going to be looking at a 4- to 6-inch lift. At those lift heights on an XJ I'd really consider a long-arm suspension. The rears should be full-leaf packs with a longer shackle. Check out Rusty's Off Road and Rubicon Express for starters. Or, if you're on a budget, Rough Country, has a really affordable 2-inch lift that you can use to squeeze some 31s under your Jeep.

The Dana 30 front should be okay with 33s and if you upgrade to alloy axleshafts shouldn't have much of a problem with 35s. As for the rear, the Dana 35 (if you've got it) is a turd-throw it away. If you've got the Chrysler 8.25 you'll be able to upgrade the axleshafts, but the gearing will be limited to 4.56. I'd really consider ditching the rear axle all together for an aftermarket Ford 9-inch with some 4.86 gears and some 4.88s in the front. This'll give you plenty of grunt off-road, while keeping the engine rpms reasonable at highway speeds with 33s or 35s.

Nose Job II
I been a subscriber for a over a year now and love the magazine. I read "Nose Job" in the May '09 issue about the CJ front clip installation on the YJ body. Is it possible to do the same, but with the TJ front clip on the YJ body?
Ricky Villarreal
Somerton, Arizona

Pete Trasborg replies: It's possible. The front end of the tub is dimensionally the same as the YJ/CJ, however, the TJ grille is shorter than the YJ or CJ grilles and is wider, so the hoods and fenders don't interchange well at all. This is in contrast with the YJ/CJ swap, in which you can keep the YJ fenders for the CJ hood and grille if you wanted. Not so without tons of body work on the TJ swap. And, as I recall, the TJ grille ends up hovering high off the frame of the YJ.

Then, there is also an interface issue at the tub itself. The TJ fenders are 1-inch taller than the YJ/CJ fenders are which means chopping the bottom inch off the fender to make it the right height for the YJ/CJ tub. Then there are the hood hinges. On the CJ/YJ, the hinges are 11/2 inches further outboard than on the TJ, which is going to mean either welding up holes in the TJ hood or welding holes in the cowl, and then drilling new ones. If you use the TJ hinge locations, you are going to get to pull your heater box, if you use the YJ/CJ locations, you will be using Bondo on the TJ hood to hide the patches.

It's harder than YJ to CJ, but not impossible. But the lines of the hood and fenders still don't line up and the gap at the front under the grill is unsightly too. Then, you get into how different the battery trays on the TJ are and the other underhood stuff that will need to get modified to work and I'd just not suggest it.

Servo Pervo
I have an '05 Wrangler 4.0L automatic which I let my grandson drive while his car was in the shop. Being a typical 17-year old boy, he had to try out the four-wheel-drive. He said he got it into and out of 4-Lo with the transmission in Drive. I have checked the four-wheel-drive function and it seems to work okay in both Hi and Lo. The trouble is, I don't hear the front axle disconnect servo as I did before. What could have happened?
Kenneth Crowe
Halfway, Kentucky

To my knowledge there are no front axle disconnect servos in an '05 TJ. In fact, I'm not aware of any TJ that used a CAD servo. Stick your head under and look at your passenger-side axle tube and you'll see that it's solid with no CAD sleeve or motor. Jeep discovered that the CAD was an unnecessary expense when used in a factory open front differential application because the spider gears inside did the job of alleviating unwanted steering input due to the lack of locking hubs on the axle. It's not until you add an automatic locker or limited slip to the front axle that you'll start getting steering feedback due to the lack of a CAD.

I don't know what noise you used to hear when engaging 4WD. The NV231 engagement process within the T-case is all manual, driven off the T-case shift lever in the cabin. Perhaps you were hearing the 4WD indicator light switch? Does the dash light still engage?

What could have happened? Who knows! Did he try to engage it on-the-fly? Drive it on the street in 4WD? Grind the T-case gear synchros excessively trying to get it in 4WD? I have no idea. I'd ask him to be honest about how abusive the engagement/disengagement was when he was driving the Jeep. If it sounded like a brick in a blender, I'd at least change the T-case gear oil. Otherwise, they're pretty durable little T-cases and I sort of doubt he did any real damage. Technically, although not a good idea, you can shift 'em while in Drive, but it's a lot easier on the T-case if you're doing a very, very slow roll while shifting. However, the proper procedure as I'm sure you know is to shift the T-case into Low with the Jeep in Park or Neutral.

Damn kids! There, I said it for you.

I have a '50 Willys pickup and was wondering if anyone made a PTO for it, or if my best bet to get one is on eBay? Your help would be appreciated.
Orange City, Iowa

There are several PTO units that were made for your Spicer 18 T-case, but none that I know of are still being manufactured today. If possible, when shopping, make sure it's for the Willy pickup/wagon and not for the CJ since the PTO clocking is a little different on the trucks than the CJs for floor clearance.

Your best bet is going to be contacting Herm Tillford at ATV Manufacturing ( It's what he specializes in and if he doesn't have the PTO you need in stock I'm sure he can tell you where to track it down.

I'd also consider eBay as a last resort, but that's just personal preference. Check out the For Sale section of or the classified section of,, and These PTO units actually come up for sale quite frequently.

Idler Hands
I have a '95 Wrangler with a 2.5L engine. I tried to change my oil in my manual transmission, but where the fill plug should be, there is a plug that says, "Don't Remove." I'm lost. Did the tranny come sealed from the factory?
Richard Tramell
Via e-mail

Yeah, definitely don't remove that plug. It holds the reverse idler gear in place. Take it out and you'll most likely be pulling your tranny to put the internals back together.

The fill plug is about half way up on the passenger-side of the tranny. Look for a Torx bolt. The fill plug is a little further back and above that Torx. It should be right near the catalytic converter and deep under the skid plate. It's not really the most accessible location, but whataya gonna do? You'll need an 8mm square socket to remove it. Some guys buy the part from the local Jeep dealer, while others grind down a socket extension to fit. Or, you may be able to find an Allen wrench in the right size that won't strip the flat sides of the plug.

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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