Eagle

I am accustomed to seeing core charges in parts stores for things that are commonly rebuilt and sold as such, like alternators and starters. Granted, I'm only 69 years old and I've only been playing gearhead since I was 14 (that's a mere 55 years), but I have never heard of a junkyard charging a core charge for something like a used axle. And the axle in that photo does NOT look like a rebuilt axle. A rebuilt would have at least had a thin coat of cheap black paint on it. I strongly suggest that you never go back to that shop for other work. He's a robber.

What size tires do you plan to run?

I think it's a great idea. Please post photos when it's installed.

2001 Cherokee -- The never-ending saga thereof. This is the XJ the seller of which really saw me coming. Every time I think I have one issue resolved, two more crop up. (Not the vehicle's fault. It has been through multiple owners and multiple auctions in multiple states, and has apparently been thoroughly abused before I got it. Lesson learned -- run CarFax before you buy, not after.) One problem is a heavy vibration that starts to kick in above 50 MPH and gets significantly worse and louder around 60 to 65 MPH. There seems to be a lot of play in the front driveshaft, at the slip joint. I'll pull the driveshaft this weekend to verify. The 2001 XJ has a LOW pinion D30. I have several older XJs for parts, with the high pinion D30. Does anyone know how much (if any) difference there is in the driveshaft length? Is there any reason I can't try a front drive shaft from an older XJ? What about ZJ front drive shafts? Are they the same length as the 2001 XJ?

For starters, check the ground strap from your engine to the firewall for continuity.

Thanks. I am taking it back to them tomorrow. Does the appearance concern you? It looks all beat to hell. It's a Dana 35 rear axle. You have a 1988 MJ. The last MJ was built in 1992 and it's now 2013, so the newest any used MJ axle could possibly be is 21 years old. The axle came from a junkyard -- seriously, what were you expecting? It doesn't look beat to hell -- it looks like it was lying in a junkyard for quite awhile, the paint got scraped, and where there's no paint it has started to rust. Wire brush it, spray it down with brake cleaner, and go crazy with gloss black Rustoleum. You had a shop do the install? The old axle is yours -- he should have given it to you, unless you specifically instructed him to throw it away.

The load (height) sensing valve will not affect the brakes dragging. But the adjustment of the star wheel inside the drums will. And if the parking brake cable is rusted and can't release completely, that will also cause the brakes to drag.

Both lamps in the MJ taillights are dual filament bulbs. They both light up one filament for taillights, and the other filament for brakelights. It's possible the brake light filaments aren't working, but it seems unlikely that all four would have the taillight filaments working and the brake light filaments burning out. Also, if just the brake light filaments were burned out, the hazard flasher should flash the fronts. I think you need to trace the circuit, starting at the brake lights and working forward.

My '88 MJ came to me with a 4" lift installed (since removed). Running 30x9.50R15s on factory Jeep rims (15x7) is no problem at all. I ran it with 31x10.50-15s on factory rims. The inside of the tires is close to the rear springs and inner fenders, but not unworkable. A day of hard wheeling would result in the upper-inner shoulders of the tires polishing the metal on the inner wheelwell liners in the rear. An inch or so more clearance would have been nice, but not absolutely necessary.

Either the line to the slave cylinder sprung a leak, or the slave cylinder itself spring a leak.

He didn't say it won't move. He said he can't shift into first or reverse. I have the same problem with my '87 MJ, but I know I need a clutch and a master cylinder. Once moving, the other gears shift, but that's because (a) they have synchros, and (b) when both the engine side and the wheel side of the drive train are turning, it's easier for the synchronizers to match things up. When the engine is running and the vehicle is standing still, even if the clutch is only dragging a little bit you can't shift into first or reverse.

There's your problem. You need a flywheel.

Yep. For a Renix 4.0L that's about the sweet spot. However, you seem to have conflicting priorities. The things you do to improve performance generally won't help gas mileage. Larger, freer flowing exhaust? Nope. Bored throttle body? Nope. 3.54 gears struggling to push 31" tires? Nope. Many years ago, when the factory exhaust in my '88 XJ 4.0L bit the dust, my brother was managing a Speedy Muffler shop. He arranged for me to get his shop price on a custom-bent, 2-1/2" exhaust system with a high-flow turbo muffler (don't remember the brand, and it doesn't matter). The result was horrible. I LOST low-end torque. My gas mileage instantly dropped between 2 and 4 MPG. And it was noisy. That was the first and last time in my life I was actually looking forward to an exhaust blowing out so I'd have an excuse to replace it. Since then I have gone direct OEM replacement from Auto-Zone. For starters, you need more gear. I ran 31s on the '88 MJ for several years, with 3.73 gears. The overall final drive ratio (as shown by actual road speed to engine RPM) was exactly the same as factory tires with 3.54 gears. I would have preferred 4.10s and I think 3.10s would have prodiced better gas mileage, but I already had the 3.73s (bought when I planned to run 30" tires), so I used them. Not horrible, but 4.10s would have been better.

Since they are all the same basic block, I would strongly advise going to a 3.1L or 3.4L if you're going through the effort of swapping engines.

Oh, bummer. I'm glad you're happy with it, but it's a short AAL, and they're generally not recommended. For just a couple of dollars more you could have bought a Rancho full-length AAL. It only lifts an MJ about 1-1/2" (maybe 2" max), but it makes the entire spring pack work much better and it rides very well. It would be a perfect match for the OME front coils, or for 1-3/4" front spacers. Yeah this one http://www.4wd.com/Jeep-Lift-Kits-Jeep-Lift-Kits-Suspension/Jeep-Add-A-Leafs.aspx?t_c=1&t_s=101&t_pt=5488&Year=1992&Make=JEEP&Model=COMANCHE&DRIVEWHEEL_VQ=4+Wheel+Drive and thanks man I could find it when I was looking earlier. That's the one. It's gone up a bit in price since the last time I installed one, but that's it. It's considered a full-length on a Cherokee, and a "long" (but not full-length) on a Comanche. Rancho's printed catalog listed it as providing 2-1/2 inches for both the XJ and MJ. I didn't see how that was possible, so I called and talked to their engineers. They said that was a misprint, and it should be 2-1/2" for the XJ and 1-1/2" for the MJ.

Wait -- What vacuum? What actuator? If the donor is a 91, it shouldn't have a vacuum disconnect on the front axle.

Oh, bummer. I'm glad you're happy with it, but it's a short AAL, and they're generally not recommended. For just a couple of dollars more you could have bought a Rancho full-length AAL. It only lifts an MJ about 1-1/2" (maybe 2" max), but it makes the entire spring pack work much better and it rides very well. It would be a perfect match for the OME front coils, or for 1-3/4" front spacers.

I think long arms are massive overkill for a 4-inch lift, but if you want long arms, IMHO you can't get better than Clayton's Offroad. I have visited their shop. No matter who you are, you can't possibly build one better, and Clayton is an industrial engineer so you also can't engineer one better.

I have adjusted steering boxes before. Sometimes it works, sometimes the box is beyond adjustment. But ... the internal adjustment of the steering box is the absolute LAST thing to consider, not the first, or even the second or third. The manual box is just a box. No hoses, no pump, no fluid reservoir. It'll bolt right in. And you'll hate it. The steering ratio for the power box is 14:1. The ratio for the manual box, IIRC, is 24:1. How many ways can you spell "S-L-O-W"? Coincidentally, I was discussing the steering box adjustment with the shop foreman at my dealership just a few days ago. He said he has done it on one of his vehicles, but he won't do it on a customer's vehicle and he won't let the techs in the shop do it, because there's too much chance of messing up the box permanently and he doesn't want the liability.

It applies to the Cherokee from the front to approximately the front seat area. In the Comanche diagrams, you can see the area under the (front) seats where the rear frame rails splice into the front unibody rails. From there back, the Comanche is totally different.

Because it raises the center of gravity considerably and the lawyers didn't want Jeep to be responsible when somebody tipped one over.

It almost has to be the neutral safety switch.

I carried a 31x10.50 spare under my '88 shortbed.

Best cam for what kind of driving? Will the engine be otherwise stock, or "built"?

The thing is, once you eliminate the height sensing valve you have NOTHING to gain by keeping both hard lines to the rear, and potentially a lot to lose. If he's thinking that keeping the second line will retain the failsafe rear brake circuit, in fact it won't. Case 1: Either rear hard line ruptures. Doesn't matter which one, they are now fully interconnected, so a leak in one is a leak in the system. Result: no rear brakes. Case 2: Front brake line ruptures. This is the condition the failsafe is intended to address. If the front brakes fail, it ensures that the rears will get 100% (rather than proportioned) braking force. But ... with the height sensing valve bypassed, you already have 100% rear braking, all the time. There is no reason to retain the failsafe circuit, because it adds nothing. But it makes it exponentially more difficult to bleed the rear brakes, plus it doubles your exposure to corrosion of the rear hard lines. In deference to your mechanic, I'm sure he thinks his way is going to be better for you. The problem is that I don't think he has any idea how that system works. I have sawed an MJ front metering block in half (the photos are on this forum, somewhere), and I know exactly how it works. Keeping two hard lines to the rear with no proportioning valve is just NOT a good idea.