Jeep Creep Answers Yours Off-Road Technical Questions

Nov. 20, 2012 By Jim Brightly
In your Jeep Creep questions, please list your first and last names, your hometown, and your state/province/country, so that we can publish that information here. If you don’t provide this information, we may not be able to publish your question and answer. Don’t forget to be as complete as possible with the description of your Jeep and its problems, too. Send your questions to editor@off-road.com, Attn: Jeep Creep.

Previous Jeep Creep Columns
October 2012

September 2012

August 2012

No Jeep recalls this month.

 

Lifting a TJ
I have a 2005 TJ and I want to know how big of a tire I can run without changing gears? I hear a lot of guys running 31s with a 3-in. lift. Does the stress of 31s cause any problems? I’m looking at an OME lift of about 2-3 inches with 30-in. tires. But if I can, I’d like to put on a 4.5-in. lift with 32s. I have a four-speed in the Jeep, but I’m not sure of the gears, although I think it’s like 3.42:1. As far as cheap, I’d like to stay under $3,000. Thanks for any help and if you can suggest what type of lift I’d appreciate it.
Pete Laska

I think you can go to the 32-inch tires, and I’d suggest Goodyear MTR tires. You’ll probably be downshifting more on hills but you won’t strain anything. And if you like the Jeep on the trail, in another year or so you’ll probably get deeper gears and a locker (with taller tires, lower gears might even improve your mileage). As far as the lift, I suggest either Rancho with adjustable 9000 shocks or Skyjacker with Softride shocks. Many years ago I tried an OME kit on my CJ and was very unhappy with it; it was so soft I scared myself on the freeway until I could reconnect the sway bars and 1 or 2 of the shocks broke before I could change it to a Skyjacker kit. Of course, things have probably improved since then. Skyjacker shocks are soft initially and then stiffen up as they compress further. Rancho 9000 shocks have nine positions of varying stiffness. I run them at “7” on my JK on the road and “1” or “2” off road to float over the obstacles.


Slippin’ Grand
I have a ‘96 Jeep Grand Cherokee with a straight 6-cyl. automatic transmission. I noticed that my transmission was starting to slip a little bit so I checked the fluid and it was really low. I put two quarts in, started it up, and shifted down the column from reverse, N, D, 2, and 1 a few times to make sure it was well lubricated. After I let it sit a little while I went for a ride and my gas pedal was stuck. I was getting a little bit of gas but the pedal wouldn’t go down so I forced it. It popped down and it was nice and loose, then the Jeep drove like I never felt it before. Then suddenly the pedal started to build tension. It now happens every time I turn the car on and put it in drive but not reverse. I had my Jeep analyzed with a computer a long time ago and the idle compression sensor was the only thing that came up so I believe I need to change the IAC sensor or the TPS sensor. Although I don’t think that’s what the gas pedal problem is. Can you give me some knowledge please?
Tyler Robillard

Not enough information, Tyler, to make a remote diagnosis. You need to take your Jeep to a competent shop and run it through a complete diagnosis program.


One-Owner Seven
I have owned my 1981 Jeep CJ7 since December 1980. I have replaced the transmission on two occasions, and the engine has been rebuilt two times. I have had clutch chatter, or at least that is what it feels like, since the early ‘80s. I have replaced motor mounts, transmission mounts, and the transmission stabilizer mounts. I’ve also replaced the clutch several times over all of these years. The only thing I can imagine is that the transmission stabilizer mount is not installed correctly. Are the rubber bushing supposed to fit tight up against the plate or should they be loose?
Blair

Transmission stabilizer is a loose fit from the factory, so leave it alone. I’m assuming that when you replaced the clutch all those times, you replaced the pressure plate, clutch disc, throw-out bearing, and pilot bushing? And had your flywheel resurfaced at the same time? If not, do all of the above to start fresh—that should correct the clutch chattering.


TJ Links
I have an ‘01 Jeep TJ four-linked up front and on the rear. I’m from Quebec, Canada, and no one up here knows what a crawler is. The entire Jeep was built by me. It has high steering on the Dana 44 and custom steering arms. It also has Fox air shocks in each corner. I have problems with my steering and also have the death wobble on acceleration. When I turn my steering wheel the body goes up and the wheels hardly turn. Also when turning with the wheels in place they turn little because the shocks go up instead. I think my death wobble and steering are the same issue. My Pitman arm is a Rough Country with at least 2-inch drop. I flexed my Jeep on the roof of an old Dodge Caravan and at low shock pressure the three wheels stayed on the ground. But when I put the shocks at 100-psi I couldn’t climb the van because half way up a rear tire was already off of the ground. When I go off-roading I need lots of flex because we go in rivers and many rocks that are four to five feet tall. What would be the best solution to my problem? I installed a sway bar and it’s much better but no more flex, and when I go in the trails I have no steering without sway bars. I think I’m at the point where I need full hydraulic steering. What do you think is the best? The shocks are so soft that on acceleration the body raises about 6 inches and pulls on the steering bar.
Andrea Reid

Your trips sound like some trips I took with the Calgary Stampeders back in the days when they could still drive on the muskeg, Andrea. Wet but fun. I would normally tell you that you need to return the Jeep to the shop that installed the lift immediately, that your problems should have been corrected at the time of installation. But since you built your Jeep yourself, I can’t do that. You have what is commonly called “bump steer” and you’ll probably need to start with a longer Pitman arm from the steering gearbox. Or the drag link’s elevation has to be changed. Your track bars and control arms are not operating properly—they may also be loose—so you still need to take it to a competent 4X4 shop to have all your suspension geometry verified. I bet you hooked your air shocks with just one air filler valve. Add an onboard air compressor and a sophisticated valving system where you can fill/empty each shock separately from the driver’s seat (this will give you unbelievable leveling control). Disconnect the sway bar when off-road to improve the articulation.


Getting a YJ High
I have a 1990 YJ with an inline 6 and 200,000 miles on her. I am learning as I go and am currently deployed in the ‘Stans so I practice my blossoming skills on our HMMWVs and a 5-ton from the First Gulf War along with a motor pool of old guys next door that speak fluent car (I do not). They often make fun of my high school shop book that I read and try to answer the questions after every section. I have leave coming up and wanted to spend my time working on the Jeep. I was hoping you could give me some advice on the type of 4-inch suspension lift I should go with and if a slip yoke eliminator is within a novice’s difficulty range. I am also curious about if I should try to switch over to a new fuel injection system. I replaced the BB with a Weber (I’m not sure about the specifics) and I’m comfortable with being able to tinker with a carburetor. I am also going to have to replace the exhaust but I don’t want to get so caught up in the work that I miss out on the rest of my time. Do you have any suggestions about how I should tackle this project and companies that I can order from in advance so that the parts will be waiting for me when I get home? I’m open to suggestions while keeping in mind that I am not looking to create anything over the top but something that can grow with me and my knowledge.
Woodrow Crosby

There’s a lot work involved with what you’ve asked about. For a supplier, I’d suggest 4-Wheel Parts (www.4wheelparts.com) or Quadratec (www.quadratec.com). You can order directly from the website and have what you need waiting when you get home. Once you go on their websites you’ll see that there are many, many manufacturers of suspensions; however, I’d suggest checking the prices and specs on three or four to begin with. Pro Comp produces fine suspensions at decent prices. I’ve used and installed several Skyjacker suspensions on Jeeps and Suburbans and have never had a failure or problem with any of them. And there are several other manufacturers.


Gearin’ Up
I`m setting up the front axle (Dana 30) in my Wrangler with a set of 4:88 gears. Instead of playing guessing games, I`m trying to figure out if anybody knows the pinion gear depth variance on the 4:88 8-tooth gear. The number is usually etched at the head of the gear and mine doesn`t have it.
Dave Southerland
Poughkeepsie, NY

Wow! 4.88:1 gears in a Dana 30 is going to give you a really tiny pinion gear—you might reconsider and use 4.56 gears like I have in my CJ7. Every gear set has a different depth unique to itself. Call the gear manufacturer for the average shim to start the setup. Randy’s Ring & Pinion has a differential book that is priceless with lots of info. Randy’s also has lots of info on the website, including a gear calculator to determine the best gear ratio for your engine, tire size and transmission gears.


Engine Swap
I have a ‘92 Jeep YJ (with the stock 4-cylinder engine) and a ‘97 Suburban (with a 5.7L V-8). I would like to swap the engine and as much of the Suburban’s drivetrain parts as possible. Can I do this and still be smog and street legal? Are there any good shops in SoCal to contact?
Kenney Rangle
Anaheim, CA

Sure, Kenney, this can be done easily with Advance Adapters’ help and kits. However, to be safe, before you begin the engine swap, contact the umpire’s division of California’s DMV and tell them what you’re planning. They can give you all the latest updates to the DMV’s rules and regulations. However, you will need to retain all the smog controls and computer from the ’97 Chevy, because the finished Jeep will have to meet the smog regulations of the 1997 model instead of the 1992 model.


Down Sizing
I have a 1990 Jeep Grand Cherokee that has a gas-hogging V-8 and an automatic tranny, which I want to replace with a 1995 Jeep Cherokee 4.0L engine and a 5-speed standard transmission. I have been a mechanic most of my life and built my first Chevy 4X4 completely from the ground up. The nice thing about the Chevys is that almost everything is interchangeable from the early ‘60s on up. I was wondering if there was a web page that dealt with the pre-1996 engine and wiring harness change out or since I have both the 1990 Grand Cherokee and the 1995 plain Cherokee as whole trucks. If I would be better off just swapping the engine and complete wiring harness along with the onboard computer. As much as I would like to have the digital gauges in the Grand Cherokee, I can live without them. Unless there is a way to convert the 1995 wiring harness to support the digital gauges, if someone could point me in the right direction. I’d be very grateful. My reason for making this swap is that the 1990 Grand Cherokee has all the extras and no body rot on it anywhere. Whereas the 1995 Cherokee needs new floors and rocker panels and is the base model with nothing extra; just idiot lights and such.
Roger Reeves
Groton, CT

First of all, Roger, buy shop manuals for both Cherokees with complete wiring diagrams. Then sit down with copies of the diagrams dealing with engine, computer, gauges, etc., and using different colored pens or pencils, blend the two wiring looms into one. You may need multiple copies because it’ll be like tracing a maze and you’ll probably take some wrong turns a time or two. In this way, you’ll end up with the best of both Cherokees.

As usual, each month, I’m shouting out a huge THANK YOU to Paul Schupp at Rock Lizard 4x4 in Kingman, Arizona, for his invaluable assistance in answering many of the Jeep Creep questions.

Previous Jeep Creep Columns
October 2012

September 2012

August 2012

Off-Road.com Newsletter
Join our Weekly Newsletter to get the latest off-road news, reviews, events, and alerts!