Eagle

And don't forget that if you are regearing, the new pinion gear has to be set for depth, and that is controlled entirely by shims. It is possible that the old shims might be right ... but highly unlikely. You need a shim kit.

The 5-speed overdrive ratio changed a few times but, in the overall scheme of things, none of them are enough different from that of the AW4 to indicate a different choice of ratio based on the transmission. As I have posted a number of times, I ran the lifted '88 MJ on 31s with 3.73 gears the entire time it was lifted and used for wheeling. 31s and 3.73s results in exactly the same overall final drive ratio as stock tires with 3.54 gears. It's very drivable on the street, but could use a bit more gear for a better off-road crawl ratio. IMHO 4.10s are the optimum gear ratio with 31" tires.

His post did not stipulate that the '89 has an automatic transmission. Also, given the frequency of the flex plate cracking, I would not do a tranny swap without replacing the flex plate. I don't want to pull a tranny and transfer case that I just installed three months ago.

Check your battery cables where they go on the battery.

The original post doesn't say what engine or tranny are in the '89. The '94 AW4 will work with an '89 4.0L, but it will require buying a new flex plate because the flex plate teeth are what trigger the CPS, and the Chrysler HO system is completely different and not compatible. Ditto if the engine in the '89 is a 2.5L, except that there you'll also need the appropriate bell housing and torque converter for the 4-cylinder engine.

Seems to me if he was a real friend he'd let you have it for $50 less than what a scrap yard would give him, or at least the same amount. I could understand a stranger holding you up for more, but a friend? That ain't right.

An internal combustion engine requires three things in order to fire and run: fuel (gasoline), air, and spark. We'll assume that you have air, so you need to verify that you are getting spark and gasoline. Gasoline can be introduced as simply as dribbling gas into the carb opening, so first you need to find out if you have spark.

The factory spec is 13 psi (minimum) at idle, and 37 - 75 psi above 1600 RPM. That's for all the engines. In reality, most tend to idle around 25 to 30 psi and run at 50 to 55 psi at normal highway cruise (60 to 70 MPH). There should be a distinct drop when you stop and the engine speeds goes down to idle. But ... the factory gauge in my '88 XJ basically sits at 40 psi no matter what speed the engine is turning. It has to be the gauge, because I've replaced the sender three times and it made no difference whatsoever. It drops to zero after the engine has been shut off, but once started it's more of a GO - NO GO gauge than a pressure gauge.

They are completely different in size and shape. I very much doubt that an XJ tank would fit unless you hung it below the frame rails, which would be a VERY bad idea.

The box is bolt-in but the pitman arm is different and should be replaced with an XJ/MJ pitman arm. As to whether the ZJ box is an "upgrade," it depends on your usage. The ZJ box has a faster ratio. That's a good thing for street driving on stock or near-stock size tires. But the ZJ box is not any bigger or stronger than the XJ/MJ box. Running a quicker ratio with large tires, especially if you do rock crawling, is very hard on the box. If anything, a rock crawler on very large tires should be going to an 18:1 ratio box rather than a quicker ratio box.

Not my problem. I don't regard that as a viable excuse. The bottom line is: If I can't read the post, I can't understand the question. If I can't understand the question, I can't provide a useful answer, so I don't even bother to post a response. The common language on this forum is English, not TXT. And, BTW, a tech question should be posted in the tech area. Posting a technical question in the Pub because you think more people might see it is a violation of the forum rules, plus it's just plain rude. Also, BTW BTW -- the seats and console from a new body style Cherokee will not fit into a Comanche without custom brackets for the seats and a bunch of carving on the console.

As CW mentioned, 3:10 was not a Jeep ratio. I had a difficult time understanding your post, until I realized that wasn't a typo but an incorrect ratio. 4.0L engine w/ 5-speed, the stock ratio was 3.07. That ratio, IMHO, was a factory mistake and should never have been used. But ... they didn't ask me. My rule of thumb for ratios, based on the vehicle being used for a mix of daily driver and moderate wheeling: 3.54 for stock tires 3.73 for 30" tires 4.10 for 31" tires 4.56 for anything larger than 31s 3.73 gears with 31x10.50 tires is EXACTLY the same final drive ratio as stock tires with 3.54 gears. (Equal final drive ratio = equal power.) There is no way 35s with 4.10s would come even close to matching the stock final drive ratio. BTW, 4.88 is an available ratio. Dana-Spicer doesn't offer 4.88 gears for the Dana 30, but some aftermarket companies do. BUT -- you have to be brave to use then, and not have a heavy right foot. The problem is that the pinion gear gets very small with the 4.88 gearset, so the differential isn't very strong. Which, of course, is the opposite of what you want when you're moving to tires so much bigger than stock. I can't imagine why you might want to put 35s on a Comanche. The front Dana 30 is a decent axle, but it's not equal to 35s. Plus, you'll have to do so much chopping that you won't have a Comanche when you're done.

XJs are spring-over, MJs are spring under. The XJ springs have less native arch than MJ springs. Using one leaf (any leaf) out of an XJ pack to replace a broken leaf in an MJ pack cannot possible duplicate the original spring's characteristics.

Oxygen sensor? Runs okay cold but goes nuts once it gets warm?

The bottom got slightly chopped off on the last version.

I'd like to see a photo of one installed. From the ad on the web site, to me it looks pretty fugly. Plus ... how do you weld the inner fender liner/wheelwell to a fiberglass fender?

Who is "they"? To whom does the land belong?

The rim size should be marked on the outside, next to the valve stem.

Of course you have crappy braking. With a lift and the rear valve still in place, you have no rear brakes. Doesn't matter how well you bleed them, the height sensing valve shuts off the rear brakes when the bed isn't loaded down. I am in the camp that says "dump it." You'll have full braking to the rear, all the time. If you find that the rears lock up prematurely, then you splice in a Wilwood adjustable proportioning valve in the line to the rear and set it where you like it. You can always dial in more rear brakes manually if you tow or hail a heavy load. I do not advise just teeing the two rear lines together. Functionally that works. But it means you have twice as much brake line running from front to rear, twice as much opportunity for rust and burst lines, and it serves no useful purpose. I pulled out both lines, and ran a single new steel line directly from the front junction block to the top of the hose at the rear axle.

That was my thought. As the little killer 'bot said in that movie, Short Circuit -- "Need more data."

Time out. Are you asking about a 1988 MJ, the one in your signature? If so, please clue us in on what changes you have made to the brakes, because what you are describing is NOT a 1988 Comanche master cylinder.

The factory lights were rectangular, don't recall if they were 5x7 or larger. I think larger. And they were not "fog" lights. Fog lights are mounted as low as possible and they have a very flat cut-off and wide, short range pattern. Off-road lights are flood lights.

Then the gauge is broken, because the actual physical range (in terms of a clock) only goes from approximately 10:00 o'clock to 2:00 o'clock. I've never seen a factory gauge on which the needle would fall not only below the "0" mark, but physically below the 9:30 or 10:00 o'clock position on the dial. It sounds like the needle was already messed up on the gauge before you started trying to calibrate it.

The idiot light doesn't come on unless the oil pressure is below something like 7 psi. If your gauge is showing anywhere near 40, it wouldn't activate the idiot light. It would also be within spec. The factory spec is minimum 13 psi at idle, 37 to 75 psi above 1600 RPM. Most NEW XJ and MJ engines typically ran about 50 to 55 psi (warm) at highway speed. 40 psi would not be at all unusual for an older engine, and would not be cause for immediate panic.

When I disconnect the oil pressure sender wire, I noticed that the gauge pegged to the right. I didn't try it with the coolant temperature sender. I will try this when I get home from work. Still need to figure out the fuel gauge....it's just completely dead. The crude "go - no go" test for the fuel gauge is the same as the others. Unplug the connector with the ignition on -- that's an open circuit (infinite resistance) -- the gauge should peg to the right. Jumper the connector to a good ground, bypassing the sender -- that's zero resistance, the gauge should bottom out to the left. (I may have the left and right reversed, I can never remember without looking it up).