Eagle

Are you really talking about death wobble? Death wobble is in the front end, and it's characterized by shaking of BOTH front wheels so violently that you almost can't hold onto the steering wheel and you're sure you're going to die, like RIGHT NOW. If your life isn't replaying before your eyes while you pray you can stop before the truck is thrown violently off the road -- it isn't death wobble. No, I am not exaggerating.

Based on the parts diagram Hornbrod kindly provided, which part do you need?

The cable in your photo is the '87 - '90 type. It is a pinch-to-release retainer. If yours doesn't come off, either you're not pinching in the right place or you're not pinching enough. There is no "single push to release" type.

How did you get it to work? You must have modified the factory wiring harness, so it might help someone else if you would explain what you did and how you made it work.

'84 through '86 Cherokee. Which part do you need, the hood side or the body side? I have an '86 XJ hulk in the back yard. Let me know exactly what you need and I'll see if it's still there.

Death wobble affects the front. Nothing about the rear axle contributes to death wobble.

No. Both stop/tail/turn bulbs on each side operate in tandem -- the dim filaments are the taillights, the bright filaments are the brake lights. The turn signals use the brake light filaments, and the turns override the brakes. Likewise, the hazard flashers override the brake lights.

Well, I'm 74 years old and I was working on cars before you were born. The way you describe may get the timing close (sort of), but it won't get it "dead on." That said, if there's no power to the CPS or coil, there's obviously something amiss. But I would suggest trying to figure out where the problem is before you start throwing parts at it. Was it running and suddenly stopped, or is this a vehicle that's new to you?

Impossible. You can't check the timing if there's no spark, and you said you have no spark.

I bought a Cherokee Pioneer new in 1988. The operable vent windows were an extra cost option, which I bought. They leaked. The factory had a "fix" -- replace the operable windows (that I had paid extra for) with fixed glass -- but they wouldn't refund the price of the option. I told the factory rep to pound sand. I smeared the gaskets with silicone grease, closed the vents, and they haven't been opened since. That was 30 years ago. Bottom line -- DON'T DO IT.

How do you know the timing is dead on if there's no spark?

That's the early type, which doesn't have the potentiometer. If it came from a V6 and you're using it with a I6, it should be okay. You can use the diagnostic connectors under the hood to connect the tach and bypass the dashboard wiring. On the passenger side, near the bank of relays, there are two rectangular connectors with yellow covers on them. The smaller one has the output and ground connections for testing a tachometer.

I've never heard of any option on the clutches, but I can say that the Trac-Lok in my 2000 XJ 5 speed is more aggressive than the Trac-Lok in my late wife's 2000 XJ automatic. The 5-speed is actually mildly annoying -- just making a low-speed turn into my driveway the clutches bind up and release with a series of loud "bangs." If your driving is 80 percent street/pavement, I'd say go for the smooth.

Right. The needles apparently can be removed -- that's how the white dial faces are installed. Personally, I'm terrified by the notion of pulling a needle off a gauge. I'm sure I'd break something trying to reinstall it. But -- if you have a tachometer that's off by 6,000 RPM -- what have you got to lose by trying? {Note: I actually don't see how it can be off by 6,000 RPM. The dial only goes to 7,000 RPM. If it's already reading 6,000 when the engine isn't running, then it'll be nearly pegged as soon as you start the engine, and if you rev the engine past 1,000 actual RPM the tach needle absolutely will be pegged.]

No switch on the 84-86 clusters. It has to match the cylinder count, there's no way to adjust it. '87 was the "swing" year. The gauge faces are the old style, and I've never pulled an '87 tachometer to see if it has the potentiometer. But -- even a wrong cylinder count wouldn't make it off by 6,000 RPM. That's past the redline with the engine at idle -- or shut off. Think about it -- the tachometer counts firing pulses. It's a 4-stroke engine, so each cylinder fires once every two revolutions. Each revolution generates 2 pulses for a 4-cylinder, 3 pulses for a 6-cylinder. So -- for a 6-cylinder 1,000 RPM means 3,000 pulses. Now connect it to a 4-cylinder tach. For the 4-cylinder, 1,000 RPM is 2,000 pulses. The tach is seeing 3,000 pulses, so it's going to register that as 1,500 RPM.

I think rebuilding the Trac-Lok is a good choice, given that your driving is 80% pavement. I definitely wouldn't go with an auto-locker. Second choice would be a TrueTrac, which is a limited slip but doesn't use clutches.

No, the early ones didn't have the potentiometer. That didn't come until the "new" instrument cluster design, in 1988. And it wouldn't make it 6,000 RPM high, anyway.

They are.

Back to the original post -- I hope your planned build is mild, because that MJ is far to nice to hack up. It should be preserved.

To me, "clutch out" means the clutch is disengaged. I think you're saying it makes noise when the clutch is engaged, and the noise stops when the clutch is disengaged. That, plus popping out of gear, says to me that the synchronizers are shot. Possibly due to using the incorrect gear lube in the transmission. Unfortunately, the factory initially said to use GL-3, but GL-3 was replaced by succeeding numbers. GL-5, which is what's generally available, has a lot of sulpher. The sulpher attacks "yellow metal" (brass and bronze). Guess what the synchronizers are made of.

Why does the fuse panel need to be replaced? Why not replace with another Cherokee/Comanche fuse panel? And who swapped in the AX-15? Is the transmission change related to the fuse panel issue?

7,000 RPM? I thought in-line sixes had a destructive harmonic at 6,000 or 6,500 RPM. There was never any reason to push an AMC (or Jeep) I-6 even to 5,000 RPM. They're long stroke engines, designed and built for torque, not high-RPM horsepower. Long stroke engines don't particularly like to rev. Among all the Cherokees and Comanches I've owned through the years, completely ignoring the AMC cars, I've easily put over a half million miles on the 4.0L engine -- probably closer to a million. I don't think I've ever taken one above 3,500 RPM, and I rarely go over 2,500. My usual shift point with the 5-speeds is between 2,000 and 2,200 RPM.

I was thinking of "around town" as being generally 45 and under -- mostly under. Going back to the root of these engines, my family was a Hudson ==> AMC family. Between my parents, my brother, and myself we've owned a number of the old AMC versions of this engine, ranging from 199 c.i.d. to 232 c.i.d. to 258 c.i.d. Also owned any number of Javelins and AMXs with V8s. All were standard transmissions, from before the days of overdrive (except as an expensive option, which we never opted for). Regardless of gearing and tire size combination, the end result was always 24 MPH per 1,000 RPM in top gear -- so 60 MPH was exactly 2500 RPM, and 3,000 RPM gave a nice, slightly extra-legal 72 MPH cruise. I know for those accustomed to newer vehicles with 5- and 6-speed transmissions the idea of running around at 2500 RPM seems like "burning up the engine," but it isn't. Don, with your tire and gear combination 50 MPH in 3rd gear should be 2323 RPM. Overdrive at 50 should be 1743. I'd probably let it go into overdrive at 50, but I'd certainly try keeping to 3rd below 50 just to see what happens.

I know he has the numbers, but I don't have them. I don't really care what the actual numbers are. The point is that his around-town gas mileage sucks. If it turns out that he's operating well below whatever his torque peak RPM is, it's very possible that his fuel economy might increase if he stays in a lower gear, to keep the engine running closer to the torque peak RPM. The AW4 likes to shift into 4th gear (overdrive) at a much lower speed than where I would choose to shift a manual transmission into overdrive, so it's worth a try. Don said he's running 31" tires and 4.10 gears. By my chart, at 40 MPH in overdrive the engine would only be turning 1394 RPM. And I think the AW4 will go into 4th at 40 MPH. At 45 MPH, it would be turning 1568 RPM. Still WAAAY below the torque peak, and probably not even sneaking into the "fat" part of the torque curve. Keep it in third gear (direct, 1:1 ratio) and the RPMs become 1859 at 40 MPH and 2091 at 45 MPH. I would think that's getting into a more useful region of the torque curve.

All things being equal (which they never are), the torque peak is the engine speed at which the engine is operating most efficiently. In a motor vehicle, other factors mess that up, such as mechanical drag and aerodynamic drag, both of which increase exponentially with speed. Nonetheless, it's worth a try. I know that here in Connecticut for many years the maximum speed limit on any highway was 55 MPH. (They've now gone back to 65 for a couple of Interstates.) My '88 Cherokee 4.0L 5-speed (stock tires and gears) only turns about 1540 RPM at 55 MPH. That's far below the torque peak, even for a Renix-era engine. The torque peak for the '88 is at 2400 RPM. I found by actual testing that my highway gas mileage was the same in fourth gear as it was in fifth. In fourth, 55 MPH is 2054 RPM. That's still below the torque peak, but at least it's getting closer. There wasn't enough difference to make me always run in fourth. I used fifth because it was there, and because it might result in less wear on the engine. But fifth was so far under the torque peak that, at 55 and even 60 MPH, most long upgrades required a downshift to fourth. So I think it's worthwhile for Don to at least try it.