Eagle

The vibration issue is basically tailshaft "whip" resulting from too much u-joint angle and load. The problem carried over to the Libertine, too, and Chrysler still didn't just do a short shaft transfer case with the slip joint in the driveshaft. On the Libertine, they hung a heavy, concentric weight on the driveshaft to dampen the vibration, neatly addressing the symptom rather than the cause.

The issue isn't wear, but an odd sensation that's difficult to describe unless you've felt it. I first encountered it in my ill-fated 1999 WJ, and I now have it in the 2001 XJ Sport (which does NOT (yet) have Up Country suspension). As you slow to a complete stop, the vehicle seems to stop normally and then, just as the wheels come to a complete stop, there's a sudden lurch almost like a car came up behind and gently tapped your bumper. It seems to be caused by the splines in the slip yoke binding as the suspension moves, then releasing abruptly when motion has stopped and the suspension settles. With the '99 WJ the dealership (and then the factory rep) told me that using a new, special grease on the slip splines would cure it. It didn't. With the XJ, the rear springs are noticeably sagged, and I expect that when I add a second main leaf to bring the ride height back up to where it should be that the stiffer rear springs will reduce spring wrap under braking and hopefully eliminate the issue.

Nope, the vibration is a result of u-joint angle combined with unsupported length of tailshaft. It affected ALL XJs with the Up Country suspension. I know -- I own two of them. I discussed it with the service manager at the dealership where I bought them, and he admitted that his wife's '99 XJ had the same problem. The factory did offer a "fix." Not a short shaft conversion, which would have been a real fix. No, the factory wanted to just install a transfer case drop to change the u-joint angle. The vibration isn't too bad on my wife's 2000 with the 242 transfer case, so I'm not worried about that one. My 2000 5-speed has a severe vibration, so I baby it when driving, and I have a short-shaft conversion sitting in the garage waiting for the day (week) when I can find the time to install it. The output shaft lubrication issue causes a different phenomenon -- a short of "lurch/bump" feeling coming from the drive train just as forward motion stops when driving and then stopping (such as a t traffic lights). I get that a lot more in the 2001 than in either of the 2000s.

There is no "electronic speedo t-case." The transfer case is the same. What changed is the output -- the "thingie" that gets inserted into the transfer case with the plastic gear on it.. The output for a mechanical speedometer is a cable. The output for an electronic speedometer is a wire. 97+ (or 96+) transfer cases are less desirable because Chysler changed the output to a long, unsupported shaft that's prone to vibrations. It has the advantage of being sealed, so if you remove the rear driveshaft the fluid doesn't run out -- but that's the ONLY good thing about it.

Yep. I'm hoping that's what it is, although looking underneath at night with a flashlight I didn't see evidence of massive fluid loss. However, I don't know how long she's been driving it like this. The last time we had a brake problem, she trashed the front rotors by driving when the pads were down to metal-on-metal. I drove it ten feet and heard the noise. I asked her about it and she said she though Jeeps always made noises like that. Mind you, she had driven it for 50,000 miles withOUT noises "like that," but ... Oh, well.

Story of my life. I seem to spend an inordinate amount of time under Jeeps replacing rear brake lines.

Renix has two coolant temp sensors (or three). The one at the left rear of the head is for the dashboard. It can be a switch (for idiot lights) or it can be a sensor (for gauges). They look about the same externally. The Renix engines have a second temp sensor on the driver's side of the block. This is the one that feeds data to the ECU, and the engine will NOT run properly without it. If you have an auxiliary fan, there's a third sensor in the driver's side radiator tank. That one ONLY controls the aux fan.

Is anybody familiar with the new style master cylinders, with the plastic reservoir? If so -- which chamber feeds the front brakes and which feeds the rear? Drove the wife's 2000 XJ this evening. Even before starting the engine I thought the brakes didn't feel right. Low pedal, soft pedal, and took a looooooooong time to slow down and stop. Mentioned it to the wife and she said, "Oh, I noticed it seems a bit soft but it's not a problem because I don't drive fast." :banghead: Turns out, it IS a problem. When we got home I checked the master cylinder, and the forward chamber was empty. Too dark to be bleeding brakes in the driveway at night, so I just topped it off and I'll delve into it on Saturday. It would help me start looking in the right direction if someone can tell me if, on the new style master cylinder, the forward chamber serves the front brakes or the rear. TIA

I think it would be good for a J20 but much too heavy for an MJ.

Did you read his opening post?

I agree. So how do they balance the 5-cylinder engine you're looking at?

I still have (somewhere) a Mopar Stage 2 camshaft kit for a 2.5L. Back when I was still active in NAXJA I corresponded back-channel with a guy from (IIRC) Montana who was running a Stage 3 cam in his 2.5L and said he was averaging 28 MPG. I'm greatly intrigued by the notion of plunking one of the new, Eurpopean CRDs that Chrysler is putting in Jeeps "over there" but won't sell here into an XJ or MJ, but I just can't make myself believe it would ever be worth the time, expense and effort involved. A cam in a freshened 4.0L is just sooooo much easier ...

I think your solution is a lot closer than you realize. Pre-ethanol, when my '88 Cherokee was still relatively new, running on the original P205/75R15 tires and with a 5-speed through the stock 3.07 gears, I got as high as 28 MPG highway and overall average was probably in the low to mid-20s. I'm not at all sure what range the factory optimized the 4.0L cam for, but I can't help thinking that a "torquer" or "RV" cam installed to optimize torque and horsepower at the low end of the RPM range would easily deliver 25 MPG -- even with 10% ethanol. Driving 5-speeds, my normal shift point is 2,200 to 2,500 RPM and highway cruise is under 2,000 RPM. Even with the automatic in my wife's XJ, highway cruise is only 2,200 to 2,300 RPM. Pick a cam grind that's optimized for the 2,000 to 3,000 RPM range rather than 4,000 to 5,000 RPM, and you should be well on your way.

I keep reading that ownership switched to Chrysler in 1987, but at least in practice that's not accurate. My 1988 Cherokee was a special order that I purchased new. The order was placed in the Fall of 1987, through an AMC dealer, to AMC. The XJ was delivered to me through an AMC dealer in late January of 1988, and every scrap of paper associated with it said AMC. There was no mention of Chrysler. Even the initial warranty issues were handled through ... you guessed it ... AMC. Nothing switched over to Chrysler until late in 1988 -- which is when things really went downhill.

The AMC V8s used a Chrysler bellhousing bolt pattern starting in 1970, so the transmissions used behind the 4.0L will bolt right up. A friend built a 1948 Hudson street rod using an AMC 390 and an AX-15 from a Cherokee. It's a sweet package, but he's careful not to use all the power in the 390. An AW4 should likewise bolt right up. IMHO the best engine for you would be a 360. The 390 and 401 were externally balanced, and you're not going to find a flex plate with the external balancing weights for a 390 or 401. The 360 heads have larger valves than the 304 -- you can't put the larger valves in a 304 because the bore is too small and you have an interference fit. The blocks are the same externally for all the AMC engines, so fitting a 360 into the engine bay is the same work as fitting the 304.

I had the flex hose between the clutch master and slave burst at a toll booth on the Massachusetts Turnpike when I was on the way to a trail ride in Maine. Had to turn around and drive 100 miles back to home base with no clutch. I'm just glad it didn't happen ON the trail ride.

Except the ZJ and TJ had low pinion front axles. They'll still bolt in, but they aren't the same.

^^^ This. But I wouldn't make a practice of it.

Basic comparison: The 2.8L (as used in the XJ and MJ) was rated by Jeep at 115 HP at 4,800 RPM, and 145 ft-lbs of torque at 2,400 RPM. The 2.5L Carbureted version (used in the 84 & 85 XJs) was rated at 105 HP at 5,000 RPM and 132 ft-lbs of torque at 2,800 RPM. (A few less horses, and almost equal torque.) The 2.5L TBI as used in the 86 - 90 MJs and XJs produced 117 HP at 5,000 RPM and 135 ft-lbs of torque at 3,500 RPM in 1986. In 1987 that was increased to 121 HP at 5,250 RPM and 141 ft-lbs of torque at 3,250 RPM. That's MORE horsepower than the 2.8L, and almost as much torque -- with significantly better gas mileage. Then we get to the "HO" (multi-port) version of the 2.5L, used in the 91 & 92 MJ. That produced 130 HP at 5,250 RPM and 150 ft-lbs of torque at 3,250 RPM. As I posted above, IMHO the 2.5L wins hands down.

I would have grave doubts about any company that (1) goes to great lengths to diss the competition, and (2) can't spell "bolt-on" correctly. When I first read their description of their rear axle kit, I thought Michael Bolton must have gotten interested in off-roading. Then I realized: "Hey! These dudes just can't spell." Imagine my disappointment.

Older S10 caps are reported to fit. In fact, I have one on one of my 88 MJs even as I type. I bought it used from a fleet truck -- the seller helped me lift it off the S10 and put it on my MJ.

I prefer not to admit just how many years I wasted looking for a source of normally closed relays for circuits just such as this -- never realizing that ALL the relays I already had offered that function just by moving a wire between terminals 87 and 87A. I don't rightly remember where and when I finally awoke to the reality, but it was without doubt an epiphany.

Use a YJ slip yoke. It's longer, and it also allows a better range of operating angle. And it's much cheaper than a new driveshaft.

The purpose of the two relays is to be able to run the FOG lights off a tap to the parking lights, so you can run them either with the low beams or -- in REALLY heavy fog, when even low beams create a blinding reflection -- with just the parking lights. But ... when the tap is from the parking lights, the FOG lights will stay on with either high beams or low beams. The second relay is wired normally closed (on), and tapped off the high beam circuit. When it sees current, it opens and turns off the FOG lights. Study Skidoo's diagram carefully. He didn't tap off the parking lights, he tapped off a circuit that's controlled by the ignition switch. Doing it his way, you don't even need the parking lights -- and the fog lights will automatically go off when you turn off the ignition. It doesn't matter if the first tap is off the ignition or off the parking lights. It's the second relay that turns the fog lights off when the high beams are activated.

So you didn't pay attention to what all of us have been telling you, and you didn't use a relay. I can tell you what's going to happen, because I did the same thing over 30 years ago with a full-size Cherokee. The headlight circuit doesn't have a fuse, there's a circuit breaker built into the switch. That switch and circuit breaker are designed to carry the amperage load of TWO headlights, plus the parking lights and taillights. By addiing two driving lights to the circuit, you have now almost doubled the amperage that's being carried by the headlight circuit -- and thus by the circuit breaker in the switch. I'll give it about six to eight months, if you use the auxiliary lights very much, before you burn out the headlight switch and the circuit breaker starts tripping open while you're driving. I absolutely promise you that having your headlights suddenly shut off while you're cruising along on a strange road on a dark night is NOT an experience you want to repeat. However ... unless you have a way to shut off those auxiliary lights, the experience WILL repeat, because whenever you run the headlights and the auxiliary lights you WILL be overloading the circuit. Why do you bother coming here and asking for advice, when people who know how this stuff works give you good advice and you proceed to ignore it? Many of us have been around for awhile, and we've already made the mistakes you haven't even thought about yet. As to your inspector and legality -- if you run a stop sign and don't get a ticket, does that make it legal to run stop signs? I've given you the law, and explained it to you. It's up to you whether or not you want to be legal. Since it's no more difficult to do it right than it is to do it wrong, I just don't understand your insistance on doing it wrong. But ... it's your life, and it'll be your ticket. At least you won't be able to blame it on The Comanche Club for telling you to do it wrong.