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November 2012 Your Jeep

Posted in How To on November 3, 2012 Comment (0)
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November 2012 Your Jeep

Inverted
I really need your help. I just “finished” the build on my ’91 YJ. I installed a Wagoneer Dana 44 in the front, an Isuzu Rodeo Dana 44 out back, a heavy-duty slip yoke eliminator, and a 4-inch Rough Country suspension. On my maiden voyage, I got stuck in a mud pit, winched myself out, and my front shackles were inverted. They had flipped backward pushing the front eye of the front springs against the frame. What caused this and how do I prevent it from happening again? I have a large off-road event coming up and really need to remedy this problem before then.
Craig Warner
Mason City, IA

The shackle inversion was probably the result of winching the Jeep out of the mud. It seems to me that the mud prolly pulled down and pushed backwards on the front axle as you winched the Jeep out. This would arch the springs and pull the shackles backwards. There are a couple of options you can use to prevent this. First you can build small snubbers that sit just behind the shackle and prevent the shackles from inverting or moving backwards too much. It’s important that these snubbers don’t hit the shackle during regular driving. They should be in a position to just hit the shackle if the suspension is unloaded. You can weld these to the frame, or bolt them in place if there are convenient holes in the frame. I have seen fancy versions of these with small polyurethane landing pads for the shackles to hit if it starts moving backwards to jagged rusty steel strategically welded to the frame behind the shackle. The second and maybe easier option is to buy and use anti-inversion shackles, sometimes called boomerang shackles because of their shape. These shackles don’t have straight sides. The sides are L-shaped or shaped like a boomerang as the suspension droops the L-shape prevents shackle inversion as it hits the frame before the spring can pop backwards.

Help, My Jeep Drools
I have a ’05 Rubicon Wrangler Unlimited with about 60,000 miles. Over the past year, I have noticed that when I fill it with gas it will routinely overflow before the gas pump automatically turns off, spilling gas down the side of the Jeep. I have done some research and the consensus is that the vent tube to the gas tank may be clogged which prevents the gas pump from sensing the tank is full and allowing it to shut off at the proper time. My questions are: Have you seen this problem and is this the likely cause, and if so, how can I clean out the vent tube hopefully without dropping the tank and taking it apart?
Rich Hunt
Albuquerque, NM

Rich, I agree with your diagnosis of a blocked filler neck vent hose. I would be willing to bet a very small sum that the vent hose is not clogged, but is instead kinked or folded and is thus blocked. There is not much room under there for the filler neck hoses to fit in certain spots. I fear that there is no good way to un-kink or clean out the vent hose other than by dropping the tank. You could pull the rear fender flare and the inner wheel well plastic liner and get some visual access to the tops of the filler neck and hoses, but I bet the kink is lower down towards the tank, and basically inaccessible without dropping the tank. If you find a kink or clear out a clog, your drooling problem…er, Jeep’s drooling problems…should clear up.

However, Trasborg’s girlfriend owns an ’06 Unlimited and here’s what he has to say about it:

My girlfriend’s Jeep does this and has done it for a long time. It seems a lot of ’05-’06 models do it. I read on the Internet that it wasn’t the filler hoses or anything else, but I was not convinced they were wrong, so I spent two days pulling her Jeep apart. The vent hose was not kinked or blocked. The lines coming off the vents were not clogged or blocked. The charcoal canister seemed to be flowing (not clogged). I inhaled a lot of fuel fumes and couldn’t find anything wrong in the system. Basically I narrowed it down to something internal in the tank. I talked to Tony Pellegrino at GenRight Off Road (genright.com), and he said he hears this complaint frequently. More on the ’05s and ’06s. The factory changed something in the tank, and we hypothesized that there is an over-achieving safety valve in the filler or an under-achieving vent valve in the top of the tank. However, Trasborg recently found out this isn’t the case, and the real cause and solution will be found in the Jan. ‘13 issue of Jp.

U-Joint Limited
I’ve been building my ’68 CJ-5 for a few years and I’m ready to build my axles now. I lengthened the wheelbase by 7 inches, am using a 4.3L Chevy V-6, TH350 tranny, Spicer 18 T-case, FSJ Dana 44s, Poison Spyder full-width kit, Rubicon Express spring-over Wrangler springs, and 37-inch tires. My plan is to run a 5.13 or 5.38 gears. If all holds up well, I may put in a Warn overdrive later. Two questions; the Advance Adapters kit for the TH350-to-Spicer 18 has a small U-joint for the front output. Advance Adapters said it should hold up fine. I was going to run OX lockers in both axles. I don’t know if the front U-joint will hold up to that or should I run a limited slip of some sort. And which gear ratio would you suggest? I don’t have a trailer so I would be driving to the trails.
Jim Tribble
Vacaville, CA

That sounds like a pretty sweet set-up, although 37s may be pushing the upper tire-size limit for locked Dana 44s in rock even if you run chromoly shafts. If I were you I’d stick to 35-inch tires, which in my opinion are a better fit for the strength of the axles and T-case. Just for reference, our ’49 CJ-3A has 35s, locked Dana 44s with 5.38:1 gears, a Buick V-6, Ford T-18 tranny, and a Spicer 18 T-case with a Saturn overdrive. We can understand your concerns with running a smaller U-joint on the front output of the Spicer 18, but I think it’s unfortunately your only option. The smaller yoke and U-joint helps deal with clearance issues associated with auto tranny oil pans like the one on your TH350. We can’t guarantee that this smaller U-joint won’t be a weak link in your drivetrain, but in our experience most driveshaft U-joint failures are related to exceeding the working angles of the driveshaft through axlewrap or binding of the joint. Another killer of driveshafts and yokes is driving on them, basically getting a rock stuck under the driveshaft so the weight of the Jeep is resting on the shaft. So if you are not totally lead footed we think you will be okay with the combo you mention. Also as awesome as the Spicer 18 is it just is not that strong since it was originally intended to transfer power from a 60hp engine to low-geared axles with small tires. I am willing to bet that if you do suffer from a lead foot, having an open front diff won’t help save the driveshaft U-joint, or the rear output shaft on the Spicer 18—not to mention axleshafts. If you do end up running a front locker, just be mindful of trying to drive out of undercuts and heavy throttle use when in rocks.

Drop-in CJ V-8 Swap?
I have a ’83 CJ-5 with a 258ci six-cylinder and I really want to swap it out for a V-8, but I am not sure what to use, can you tell me what would fit without going through a lot of trouble or expense and will it bolt up to my transmission? I was told that a Ford 302 V-8 would bolt up to my motor mounts and transmission without any problems. Is that true? Thanks for the help and keep up the great work
Kenton Self
Via email

Unfortunately there is no V-8 that will bolt directly to your motor mounts and transmission. The good news is if you can imagine swapping a given engine in a CJ, someone else has probably done it. Also there are adapters, motor mounts, and other bolt-on parts available that make it almost bolt in. You will have to use adapters to get the engine to fit your transmission and you may need to weld in or fabricate motor mounts, shorten and or lengthen driveshafts, bolt on headers, and so forth. Check Advance Adapters (advanceadapters.com) or Novak Conversions (novak-adapt.com) for starters. Depending on what transmission your CJ has in it we would go with a Ford 302 or a Chevy 305/350. Both have been swapped in to a Jeep like yours before, adapters and motor mounts are available, and both will provide plenty of power for the old CJ-5.

Check Randy Light?
I just read Randy’s Electrical Corner on wiring a switch to manually turn on the electric cooling fan in the July issue. My question was that if I were to do any one of the three options shown, wouldn’t they cause my check engine light to come on? If you could please get back to me with an answer or a solution I would greatly appreciate it. Thanks for the great magazine and keep up the great work!
Donald
Via email

Randy Responds:
Earl and I stole…er, borrowed, a ’98 Cherokee for that article, but I have also wired up a few older Cherokees the same way and had no problems with the check engine light. I haven’t tried it on a newer Cherokee (’99-’01), but I would be really surprised if the engineers changed the computer controls enough to monitor the electric fan in the last three years of making the Cherokee. By the way, I have always wondered what train drivers know about car computers any ways? A simple way to check if this wiring set up would trip a check engine code on your XJ would be to fire the Jeep up, turn on the A/C, and then once the fan comes on, unplug it. If the light comes on, you got your answer, but I am betting it won’t, regardless of what year your XJ is.

Write Us!
Got a tech question you’re just itching to get answered? Send it on in to Jp magazine, Your Jeep, 831 S. Douglas St., El Segundo, CA 90245, or e-mail it to verne.simons@jpmagazine.com.

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