Eagle

3.07s with 235/75-15 tires is very workable -- it's only one tire size larger than what came stock on most of the late XJs. (Early XJs, even with the 4.0L, mostly had 205/75s or 215/75s.) Where you will be wanting more gear is when you move up to 31" tires. Can you drive on 31s with 3.07 gears? Yes, you can. I currently have the 31s from my '88 MJ on my stock '88 XJ with 3.07s. I can drive it, but it's doggy, and I am pretty well convinced that it actually hurts my fuel economy.

With 4.10s and 31 inch tires your city mileage will probably be better than what you get now. Highway mileage will depend on how heavy your foot is. My '88 with 31s and 3.73 gears got 19 MPG highway.

Yes, I believe it will be hot. It's 12 volts from (through) the gauge to the sender, and the wire grounds to the block through the sender. If the wire weren't hot, that would mean the system is sending 12-volts through the block and out through the oil sender to the wire. 1990, so it's a Renix and has the "old" wiring. The resistance of the oil pressure sender varies from 0 to 88 ohms, with 0 ohms (no resistance) being 0 oil pressure, and 88 ohms being max (80 psi). A quick test is to take the wire off the sender, with the key on, and ground the wire directly to the block. That will be zero ohms of resistance, and the gauge should then read zero. Remove the wire and the gauge should swing all the way to the opposite end, to or beyond 80 psi. If the gauge doesn't read zero when the wire is grounded directly to the block, you have an open circuit somewhere between the sender and the gauge. If it does go to zero when you ground the wire, most likely the sender is faulty.

How's your ground from the engine block to the body?

My rule of thumb is 3.73s for 30" tires, 4.10s for 31" tires, 4.56s for 32" tires, and 4.88s for anything larger than 32". For reference, I ran my '88 SWB with 31s and 3.73 gears. The overall final drive ratio (as determined by road speed per 1000 RPM) was exactly the same as my wife's bone stock XJ 4.0L with automatic.

The wiring is already in place for the tach to work. The fuel gauge and voltmeter should also work with no changes necessary.

The tachometer will work, but the temperature and oil pressure gauges won't. The idiot light senders for those are simple ON/OFF switches. You need to change the sensors to the ones for gauges, which aren't switches but variable resistance senders. No wiring is needed, just swap the sensors.

Photobucket. Flickr. Tinypics. Image Shack. All free photo hosting sites. Heck, I think even Kodak may now offer free photo hosting.

1. You don't have an AX15. It was only used behind the 4.0L from mid-1989 on. You have an AX5 or possibly a T-5. 2. No cutting of fenders is necessary to fit a 4.0L into an '86, but cutting and/or reshaping of the firewall might be necessary. Of course, since you have the '89 donor vehicle, you could graft in the '89 firewall. 3. As to the XJ with the rusty frame -- the XJ is unibody. It doesn't have a frame.

If you are really going to remove the a/c, do it right and find the factory idler pulley and bracket. Or do as suggested above and convert the compressor to on-board air.

Your shackles (the Y-shaped middle part) look better than 98 percent of the XJ and MJ shackles I've seen. What you have hardly even qualifies as surface rust. Take 'em off, buff them on a wire brush wheel, and paint 'em up with a couple or three coats of semi-gloss Rusteleum black and they'll be better than new. The lower bolts through the spring eyes are 14mm, flange head bolts. You won't find those at Lowe's or Home Depot. Considering the lack of rust on your truck, I would have zero hesitation to reuse them. Wire brush them to remove any surface rust, and coat the shanks with anti-seize when reinstalling. Use blue Loctite (not anti-seize) on the thread area. In your first link -- that photo does NOT look like the XJ shackle on Crown's web site. And -- the same shackle doesn't fit XJs and MJs. And Crown doesn't list one for the MJ. So ... Second link is a lift shackle, and it doesn't look like a Crown part, either.

If you have the glass, you are thre--quarters of the way. The whole window is glued into the body like a windshield. The outer "gasket" is trim. The slider assembly has a top rail and a bottom rail, with the ends open such that, on the ends, the glass is glued directly to the body. I don't think there's enough vertical clearance to pop a new slider glass into the tracks in the vehicle, so I believe you will have to remove the entire window assembly, spread the top and bottom tracks to insert the new glass, and then reinstall the window and the trim gasket.

Brute force. There was a special tool for that job. I needed it a few years ago so I went to the dealership and hit up my friend, the shop foreman. He sadly informed me that they had cleaned out and reorganized the tool room a couple of years previous to make room for tools to service the newer vehicles, and that was one of the tools that didn't make the cut. He said they probably had it for twenty years and he never saw it used.

I don't think it can be replaced -- because it doesn't exist. Tye MJ rear sliders aren't flat, the glass is curved, and nobody makes replacement glass for them. I know -- I have a friend who runs a glass company, and we've searched.

I was going to suggest Crown, but they only have them for the Cherokee.

4-1/2" difference between the front and the rear, or the front sits 4-1/2" lower than what the factory spec is? The nominal factory ride height for a 2WD is 6-3/4" front and 8.2" rear -- that's a difference of an inch and a half. If your front has sagged 3 inches, the LAST thing you need is a SOA lift in the rear. That's going to lift the rear a minimum of 5-1/2" to 6". What you need is a pair of new front coils. Junkyard coils from a V8 ZJ Grand Cherokee (1993 thry 1998) will bring you back to stock heit plus a little more, and still ride well.

You can run 31s with NO lift. For a vehicle that will be mostly a daily driver, don't lift it at all. I bought my '88 MJ with a 4" lift on it, and putting it back to stock height was one of the best decisions of my life.

Rotors are rotors. As long as they run true, any is as good as another for stopping. Cheap rotors warp if you just look at them. What you need to look at is pads. I don't know if semi-metallic or ceramic pads are better, but either will be an improvement over OEM replacement grade pads. One thing about semi-metallics: If they operate like full-metallic pads for race applications, they work better when hot -- which might not be ideal for a street vehicle. So the ceramic pads might be the way to go. Also, are your rear brakes working? Do you still have the rear height-sensing proportioning valve? If so, it it correctly adjusted? If not, you may only have brakes on the front wheels. Getting the rear brakes back in the equation makes a big difference.

No dealer keeps Performance Catalog parts in stock, but they can order them and have them in 2 to 3 days. They are cheaper from a jeep dealer than just about anywhere else, and they're very heavy duty and high quality. (They should be -- they are intended for use on high horsepower drag race cars.)

I think you are describing a thin metal disk? If so, it's just a dust cover to keep large debris out of the axle tube, it's not a seal. But I'm confused by your use of the term "spindle," since only the early 2WD XJs and MJs have a spindle -- and it doesn't enter the axle housing. Are you referring to the front axle shafts, inboard of the U-joints and stub axles? Look at this: http://www.quadratec.com/jeep-replacement-parts/cherokee-xj/xj-dana-30-front.php Are you asking about the disk at the left end of part number 23? (Actually, I guess the disk is part number 23.)

http://www.mopar.com/assets/pdf/performance/catalog/Steering_Suspension_&_Brakes.pdf Scroll down to page 10 (page #134 on the page image). Go back and tell your dealer's parts monkey to get his head out of his posterior.

I think at your traffic light incident you yanked on the shifter when the clutch was engaged, and the result was that you pulled the shift levers inside the tranny out of their proper seats. I'm not sure that can be fixed without opening the tranny. Several people have told me it can be done, but I've never had any luck when I've tried it.

Ain't that the truth. Two years ago I bought a used 2001 XJ with the intention that it would be my daughter's when she got her license. The license hasn't happened, and she's away at school, so I've been driving it. The day I got it registered, I slapped the plates on it and drove it to my friend's house (about 3 miles) to show it to him. The brakes felt a bit funky, so we checked the master cylinder. Empty. Well, it was used, and it had 80 something thousand miles, so maybe the previous owner wasn't paying attention. We filled it up, I drove it home (3 miles), and when I got home the MC was empty again. Now ... this XJ was originally sold in PA, spent some time in NY and then some time in NH. It was last titled in Maine before I got it. All rust belt states. I wound up replacing every hard line in the brake system except the short one on the left rear ... all the others were ancient history. Last week I lost the brakes again. I'm sure I don't need to tell you which line let go. The MJ brake lines to the rear like to rust out where they pass between the frame and the gas tank. It's almost impossible to inspect visually. If you don't live in a rust-free area, IMHO it's always wise to just run a new line if you're eliminating the height-sensing valve. It's cheap insurance, because when (not if) it pops you'll be doing it anyway.

Not really. Look at specs for so-called "RV" cams. Typically, they are higher lift than factory cams but shorter duration and less overlap. Their purpose is to increase torque at the low end rather than horsepower at the top end. When I built the first engine for my Javelin race car "back in the day," the cam maker completely misunderstood the performance characteristic I had given him and he gave me ... an RV cam. Gobs and gobs of low end, but where the factory engine would rev to 5500 and stop there due to valve float, the "race" engine was all through at 4500 RPM. Literally ... in top gear that was as fast as it would go, because aerodynamic drag exceeded the available power. Needless to say, I swapped out that cam post-haste. See if you can dig up the specs for the factory Stage 2 cam kit. That would probably be a good target for you. If you might be interested in a factory Stage 3 kit, one of my friends from NAXJA had one. I don't think he has sold it, but he no longer has the 4-banger MJ so he would probably be willing to part with it. If you're interested, send me a PM.

That all depends on who you get the lift springs from, and whether or not they are built to the same capacity as factory standard springs. Remember, even a stock MJ has (had) a load rating of 1475 pounds. That's basically a 3/4-ton truck. The metric ton springs and D44 axle raised it to 2200 pounds. Towing should not even be an issue, because the limiting factor is going to be the tongue weight on the hitch (typically 300 pounds or 500 pounds). Beyond that, what counts is the ability of the drive train to pull the weight, and the ability of the brakes (and truck) to stop it.