Eagle

You do NOT have death wobble. You have tire shimmy. Read other threads on death wobble. You do NOT accelerate through death wobble to see if it'll go away at 62-1/2 MPH. When death wobble strikes -- you hold on for dear life, stomp on the brakes, and pray to the deity of your choice that you can control the vehicle long enough to get it stopped. No, that is NOT an exaggeration. Your clue is two-fold: (1) it began when you changed tires; (2) it kicks in at 50 MPH and it stops at 60 MPH. Classic symptoms of wheel IMbalance. The reason the plow stops it is that the plow puts a lot more weight on the front wheels, so there's a lot more resistance to wobbling. It's just about impossible to bubble balance larger, wider tires. Heck, when you get into larger LT sizes, most shops can't even get 'em balanced right on their fancy, high-tech computerized spin balancers. Balance your tires correctly and you won't have any more problems.

I have been told more than once that the moon is made of green cheese. More recently, I have read right here on the Internet that the United States never landed anyone on the moon, and that the space station doesn't exist because anyone going into space would be instantly killed by solar radiation. It MUST be true, because I read it on the Internet. I own multiple XJs and multiple MJs. I have wheeled both my primary 1988 XJ and my primary 1988 MJ. All doors still close. Take it for what it's worth.

I don't, but several of my friends in the North Atlantic Chapter of NAXJA do. Clayton's old shop used to be just a couple of miles up the road from my brother's house, and I went over and lurked while they installed one of the kits for one of the NAXJA-NAC guys. It's a top-grade kit, and it works. What more can I tell you?

No.

As a certified "Tread Lightly!" Master Trainer, I'll have to disagree with you. Tread Lightly means doing as little damage and leaving as little impact as possible -- including simply not going certain places if you can't go there without leaving a severe "footprint" (such as not driving across boggy terrain during the wet season, for example). It also means things like not driving with a heavier foot than necessary for the conditions, not straying off the prescribed trails, not making multiple detours around the detours -- all that good stuff. Tread Lightly! certainly doesn't encompass cutting down trees to unstuck yourself. If the only way to get out of somewhere is to cut vegetation, the Tread Lightly! approach would be ... don't go there. It's about being responsible stewards of the land, not only to preserve the environment but also to preserve whatever level of access to it we currently have. Irresponsible wheeling just gives the rabid tree huggers more reason to argue that we should never be allowed to wheel, anywhere, any time.

They don't work for me.

Butyl adhesive.

He doesn't have a serpentine setup. I'll try to take pics of both the '86 and the '88 over Thanksgiving and post 'em up.

There is a fuse for the gauges. It is located in the fuse panel, which is beside/above the driver's left foot. The fuse you are looking for is located toward the bottom right corner of the fuse panel, next to the top of the hazard warning flasher can. It takes a 7-1/2-amp fuse. Check that first.

Measure again. A 4" lift typically moves the axle less than 1-inch, more like 3/4 of an inch. A 2" budget boost shouldn't shift the axle more than maybe 1/4 of an inch. Either you're not measuring correctly, the truck isn't sitting level when you measure, or you have other problems.

^^^ What he said. Exactly.

The 545RFE is the transmission that was in my 1999 Grand Cherokee. Let me put this in perspective: I bought a 1988 Cherokee in January of 1988. Ten years later it had about 175,000 miles on it and I thought it ws getting tired, so I bought a 1999 Grand Cherokee in January of 1999 to replace the 1988 Cherokee. Chrysler bought back the '99 in October to keep me from filing a "lemon law" complaint. I still have the '88 Cherokee. It now has 290,000 miles on it. The 545RFE transmission was one of the major items of complaint I had with the Grand (along with the transfer case and the rear axle, and the front discs warping on a weekly basis). There's just not that much difference between a .75 final drive and a .67 final drive. Run one size larger tires and you've got the equivalent. That transmission is JUNK. (But ... it's from Chrysler, so saying it's junk is rather redundant). The AW4 is infinitely superior.

Why? They are inferior in every way to the AW4. Why would you want to put one in an MJ? Heresy!

DOT 5 is made as brake & clutch fluid. It is completely compatible with DOT 3 and DOT 4 fluids. It won't mix with them, so if you have both fluids in one system they'll be completely stratified and separate, but they'll coexist happily for years. The reason not to do that is, once you put any DOT 3 or DOT 4 in with the silicone, you lose all the non-hygroscopic advantages of the silicone. The U.S. Army has used nothing but DOT 5 silicone for brakes and clutches in military vehicles for something like 25 years. I use only DOT 5 silicone in the brakes and clutch system of my XJs and MJs, and I haven't had any problems whatsoever. I started using it in my race cars about 35 years ago, before I even bought my first XJ. I won't use anything else in a Jeep I intend to keep. The only caveat is that you should NOT use silicone in an ABS system. There are so many different reasons given that I won't even get into it. Chrysler engineers can't tell me why -- they think it comes from the siicone manufacturers. And Dupont engineers can't tell me why -- they think it comes from the car manufacturers. The only thing they agree on is, don't use it in ABS. Fortunately for me, I don't own anything with ABS so it's a non-issue for me, but I have to pass it along when I recommend silicone brake fluid to everyone else.

Nobody mentioned a transfer case drop, except you. Are you asking about MJs in general, or do you know if you'll be working on a longbed or a shortbed chassis?

No, it won't. When the injectors and the ignition fire are controlled by the CPS. The only thing turning the distributor housing does is assure that the rotor is actually aligned with a turret when the ignition fires. That's normally not needed with a stock engine, but some aftermarket cams don't have the distributor drive gear aligned correctly and that makes it necessary to cut off the ears and "index" the distributor housing.

6-cylinder ZJ springs won't change your height at all, and V-8 ZJ springs will give you a 1" to 2" lift. What is it you're trying to do, again?

No, but I can give you the official, factory tech bulletin method of measuring: Top of axle tube to underside of frame rail, straight up. Be sure to measure from the actual tube, not from any brackets or the disconnect housing. 2WD should be 6-3/4" plus or minus 1/2". 4WD should be 7-3/4" plus or minus 1/2".

Trust me ... you don't want to know. When you find shops offering to do it for $100 an axle ... just remember, "You get what you pay for,"

Ummm, 2,788 RPM maybe? Ummm ... maybe. Dang typos ...

No, it's not "ridiculous." It's pretty well accepted Jeep lore. Of course, how valuable your time and effort is to you may be different from how valuable my time and effort are to me. It's a LOT less effort and time to add a pair of perches to an XJ axle (or even to burn or grind off the originals and relocate them) than it is to set up a differential. As to the worth of the results; I'll just post the figures and each reader can make their own decision. These figures were all derived using actual tire manufacturers' revolutions-per-mile from their web sites or sales brochures, so there's nothing theormetical here. And to avoid differences due to the several overdrive ratios used in the XJ and MJ over the years, I'll post only the 4th gear (1:1 ratio) numbers. 3.07 gears / 225/75R15 tires: 26.75 MPH/1,000 RPM 60 MPH = 2241 RPM 3.55 gears / 225/75R15 tires: 23.21 MPH/1,000 RPM 60 MPH = 2584 RPM 3.55 gears / 31x10.50R15 tires: 24.93 MPH/1,000 RPM 60 MPH = 2407 RPM 3.73 gears / 31x10.50R15 tires: 23.65 MPH/1,000 RPM 60 MPH = 2536 RPM 4.10 gears / 31x10.50R15 tires: 21.51 MPH/1,000 RPM 60 MPH = 2788 RPM You want to go through all that work to make a ratio change that's about 15-1/2%. The tires you're running are 6.8% bigger than stock (in terms of actual revolutions per mile, which is what counts), meaning your net improvment for all that work is going to be 8.7%. Maybe that's worth it to you, but having driven and wheeled 31s with 3.73s, there's no way I'd even consider doing 3.55s. Those who have been around here may recall that the reason I ended up with the 3.73s was an accident anyway. I had done the numbers, and I bought the 3.73 gear sets with the intention of installing in my Cherokee to run 30x9.50 tires. Then a Comanche with a 4" lift followed me home. My brother gave me the old 31x10.50s off his Nissan. The MJ had 3.07s, which sucked predictably with the big tires. Rather than buy another set of gears, I just threw the 3.73s into the MJ. They were fine on the street (about like 3.55s and stock tires, as I said above), but not enough gear for wheeling. 4.10s would have been optimum for wheeling, and still very good for street. But ... do what you want to do. It's obvious you didn't come here to ask for advice but to tell us how much you know and how little we know, so ... enjoy the work.

Backlash is only part of the issue -- setting the pinion depth for proper engagement is perhaps even more critical. That's hard to do without the proper measuring equipment, or lots of gear-marking compound and trial-and-error. Second point -- used gears are almost always noisy, because there ain't no way you will ever get them set up exactly the way they were run in before. You may have them set up "correctly," but they won't be the same. Lastly, it's just not worth the effort to go from 3.07s to 3.55s with 31" tires. I ran 31s with 3.73s. The overall final drive ratio works out to exactly the same as 3.55 gears with stock tires. So by going to 3.55s with the 31" tires, about the best you'll manage to do is get back somewhere in the area of stock 3.07 gears and stock tires. You probably won't have much luck finding 3.73s in a junkyard, because that wasn't a common ratio. But most 4-banger XJs and MJs had 4.10s, and that's the optimum ratio for running 31" tires. My humble advice is to not waste any time, effort or money on the 3.55s. Just look for a set of JY axles out of a 4-cylinder XJ or MJ and throw those under your truck.

You wanna explain why you need 450 horsepower for a trail rig -- a vehicle that crawls along at less than 10 MPH at under 1200 RPM 95% of the time? If you want to throw money at an engine, by all means have fun throwing, but IMHO you should at least have some sense of where the project is going. Horsepower in a trail rig is wasted. You can build great trail rigs on the Jeep 2.5L engine. It's only on the highway that engine doesn't measure up.

Chances are your bad alignment screwed the tires up pretty good. Get it aligned, you can try balancing them, but I wouldn't be surprised if you need good ones. Doing the alignment yourself is pretty easy... and free! http://www.4x4xplor.com/alignment.html That is only a toe & steering adjustment...not a complete alignment though ;) Correct. And caster angle is important in solid front axle vehicles. Insufficient caster WILL allow death wobble to show its ugly face.

I don't think you have death wobble. I think you have shimmy caused by tire balance. Let's be clear about what death wobble is. Death wobble is called that because it's SO severe that when it kicks in, you pee your pants and you KNOW you're going to die before you can stop the vehicle. If you had death wobble kick in at 53 MPH, there is no way on God's green earth that yu would or could keep driving through it long enough to get over 67 MPH and have it smoth out. Quite frankly, you would lose control of the vehicle and crash long before you got to 67 MPH. You don't drive through death wobble until it smooths out. The only way to stop death wobble is to stop the vehicle, or nearly stop it (meaning getting down to about 15 MPH or less). Have your tires balanced.