Eagle

The transmission won't mate to a 4.0L engine, and wouldn't handle the torque if it could. The transfer case is an earlier and weaker design than the NVG 231 or NVG 242, has poorer internal oiling, and the low range is 2.60:1 rather than 2.72:1. The front axle will work. The rear axle will work, but it's almost certainly a Dana 35, so not especially desirable. However -- if it's a 5-speed, the axles should be 4.10s, which is a nice find and certainly worth the price (free).

I recall reading that, too, but I never followed up on it so I can't attest to the accuracy of the statement.

I wouldn't expend any money or effort converting a Dana 35 out of anything to put in an MJ. It'll still be a Dana 35. Keep working on getting the drums off.

Agreed. 10W30 should produce adequate pressure, absent other issues.

What brand of oil, what series, and what weight?

Factory spec for warm (operating temperature) oil pressure is 13psi minimum at idle, and 37 to 75 psi above 1600 RPM. Typically, my experience has been that ***most*** healthy 4.0L Jeep engines idle at 20 to 25 psi and run 50 to 55 psi at 2000 RPM (highway cruise). Oil pressure as low as you are seeing probably indicates bearings, and those can be replaced with the engine in the vehicle. In fact, a number of years ago I hosted a meet-n-greet, BBQ, and trail ride for the NAXJA-NAC chapter. Folks showed up at my place on Saturday, we had a huge cookout Saturday night, everyone camped in the field in front of my house Saturday night, and we did a trail ride on Sunday. One of the guys dropped his oil pan and replaced main and rod bearings while we were cooking dinner. [Edit]Forgot to ask: What brand oil filter are you running? I'm not sure why, but Fram oil filters cause low pressure problems on Jeep engines. Also, what brand, type, and weight of oil are you running?

Coil pack? I'm on the third one in my late wife's 2000 XJ.

How to measure ride height (and lift):

NGK

Back to basics: "Lift shocks" don't lift the truck. They are longer than stock, to be used in a truck that has been lifted, but the lift has to be accomplished by different springs or other mechanical modifications. You can't just buy a set of shocks and get the truck lifted (if that's what you had in mind). The only exception is Monroe Load-Levelers, which are shocks that have helper springs built into them. BUT ... Monroe doesn't list a Load-Leveler for the MJ. You can do a deep dive through the Monroe technical literature and figure out what Load-Leveler will fit, but the amount of lift you'll get will be unpredictable.

Be sure you get the correct year. 1986 thru 1990 were metric thread. 1991 and newer were SAE thread.

Hell with the tie rod end -- what's with what appears to be a 3-piece drag link held together with 1/4" U-bolts?

Dang -- it's in MY state! And I need a new boiler and a new roof on the hovel. Timing couldn't be worse. I would SOOOOOO love to have that.

I believe the Ford rims also have a smaller center hole and won't seat properly on Jeep hubs. Not certain of that, but that's what I remember.

Remove the spark plugs and run a compression test. It's very likely that at least one of two things happened -- and maybe both: 1. The head warped and blew a head gasket 2. It got hot enough that the rings initially seized in the bores when you shut it off hot. The cylinder walls may be scored, and the rings have probably lost their temper, so you're not getting good compression. Unfortunately, I suspect that the engine may be toast at this point.

Yes, that vehicle will really stand out ... in Mexico. Except that it's already been painted some other color.

I use one from either Auto Zone or Walmart. It fits, and it does the job. There's no way I would pay more than $10 or $15 for one of those. The cheap ones do just as well as the $60 model.

Is there supposed to be an engine underneath all that plumbing and hardware?

Clutch type limited slip differentials are really intended for street driving in rain and snow, not for hard-core wheeling and rock crawling. They aren't "lockers," they are what they are -- slip limiting devices. A better type of limited slip for off-road use is the Torsen type, which is mechanical. The Tru-Trac is similar to that; it's an all mechanical differential, so it doesn't require the use of friction modifier. That's what I have in the rear of my 88 MJ Chief, and it works very well. It's transparent on the road -- you don't even know it's there -- but it has worked well wheeling with NAXJA-NAC at the old Paragon Off-Road Park in Pennsylvania, and in snow on the street. I don't think it's robust enough for really big tires on slick rock such as at Moab, though. The life span of a Trac-Lok depends partially on how much abuse it gets, and also on whether or not you maintain the friction modifier. A Trac-Lok defaults to being engaged. The clutches are in contact all the time. They allow the two wheels to rotate at different speeds only when the torque differential between the two wheels exceeds the limit -- such as when going around corners on dry pavement. In other words, it's "locked" until there's enough torque to make the clutches slip. The limited slip diffs in the WJ Quadra-Trac system work just the opposite. In that system, it's still a clutch system and requires friction modifier, but it defaults to being UNlocked. When the speed difference between the two wheels exceeds some limit, a "gerotor" pump in the diff applies pressure to engage the clutches. I always wondered if we could retrofit the Quadra-Trac diffs to XJs and MJs, but I've never had the time or money to pursue it.

No springs. The clutches are pre-loaded by adjusting the shim pack. The original Trac-Lok in my 88 XJ finally gave up the ghost ate around 150,000 miles. The guy whose stock car I used to crew on was also the service manager at my Jeep dealer, and prior to becoming service manager he was their top mechanic. Instead of buying a new Trac-Lok unit, he re-shimmed it and I got another 50,000 miles out of it. The downside to a Trac-Lok is that it IS always engaged ... until the difference in torque from one side to the other becomes great enough to overcome the friction in the clutches. That's what happens when you go around corners on dry pavement.

According to that article, the 0630 and the 7120 take a different valve cover, and they aren't interchangeable.

Is that article missing a head? I thought the early 2000 4.0L heads (#0331) were prone to cracking and had been replaced by a different casting number. The article says the 0331 was used from 2000-2005. Found it: https://www.naxja.org/forum/showthread.php?t=1076299

If the heads were exactly the same, they wouldn't have different casting numbers.

Respectfully, assumptions don't indicate anything. What would indicate spark is pulling a spark plug wire and seeing a spark when cranking. You could have a coil that doesn't generate enough spark for starting when hot. The vehicle starts when cold, so the choke must work when cold. But does the choke stay open for hot starts, or is it closed and causing an over-rich mixture that can't fire?

"No combustion" would indicate a lack of spark. Have you checked for spark? Is the choke adjusted correctly?