Eagle

Okay, I sort of got lost as to what's original and what was swapped in, but here are some thoughts: 1) Is this an automatic? If so, how's the neutral safety switch? If it's a manual tranny and you swapped in anewer harness, somewhere in the early 90's Chrysler added a clutch safety interface -- the engine can't be started unless the clutch peddle is depressed. I don't know where that is or just what it looks like, but it's something to consider. 2) The CPS and ignition for the HO are totally different from the '87 - '90 Renix system. You have to use the CPS that matches the year of the engine and ignition -- the HO CPS won't talk to the Renix ECU, and vice versa. 3) In 1991 Chrysler rewired the entire vehicle, and one of the changes was to reverse the polarity of all the instruments. If you're wiring didn't take that into account, it may be possible that you fried something important, but I don't know enough about your swap to offer any guesses as to what might have been cooked. Best I can think of would be to get yourself the elctrical diagrams for the vehicle, and for the harness you swapped in. Replicate the replacement on paper and see if you can spot any areas where the polarity shift might have an effect on what you swapped in.

You aren't supposed to resurface the flywheel on an XJ or MJ. I believe it says that right in the factory service manual. Everyone I know of who has allowed a shop to do that has experienced problems. It can't be fixed, because it shouldn't have been done but the shops aren't about to 'fess up and buy you a new flywheel.

Clayton's Offroad in Waterbury, CT, has a bracket kit for installing front axles from a full-size Cherokee/Wagoneer into an XJ or MJ.

The hidden winch option was not a winch bumper. It used a 5000 pound Ramsey winch on an angle iron frame that mounted BEHIND the bumper. The bumper itself is a stock bumper with a slot cut in it. I never see them here in the U.S., but when I visit my wife's family in Chile I see them all over the place. Somewhere I have a dimensioned drawing of the winch frame. It mounts vertical, not flat, so unless you can find the special Ramsey winch that the factory used you have to "clock" the winch so the feet point toward the rear of the vehicle rather then down toward the ground.

No. I have yet to wheel with anyone whose air locker actually works more than about 65% of the time. I am confused. Your first post said this is a street truck. Then later in the thread it sounds like this truck sees the drag strip. Drag racing is not "street only." You have to realize that the two are almost mutually exclusive. For "street" a limited slip, like a Trac-Lok or TrueTrac, is by far the better choice. If you are drag racing, the ONLY choice is a Detroit Locker. Drag racing chews up the clutches in a typical limited slip very fast, and that applies both to the Jeep/Dana Trac-Lok and to whatever Ford puts into the 8.8 from the factory. The TrueTrac locks up more positively, but even for street use it is only guaranteed for up to 32" tires. I don't know how well it would hold up to doing hole shots, and when it breaks I doubt it'll be warranteed. Detroit locker. Only choice.

You need to brush up on terminology. A "posi" is a limited slip. Speficially, "positraction" was a GM trade name for their factory limited slip diffs. What you're saying is that you don't want a true automatic locker, like a Detroit Locker. For a street truck, I agree with you. Your least expensive option is a Dana-Spicer Trac-Lok ... the same unit the Jeep factory offered as an option. The biggest downside (and it isn't big) is that the clutches wear out after maybe 100,000 to 150,000 miles, and you have to use friction modifier in the gear lube. For a little more money you can get a TrueTrac, which is a gear-driven limited slip. It doesn't require special lube additives, it's a bit more aggresive than a Trac-Lok, and there's nothing to wear out. I have a Trac-Lok in my XJ, and a TrueTrac in my MJ. Neither one scrubs the tires on dry pavement. I think you'll be wasting a lot of money buying an air locker for a street truck.

You can use the dash-mounted vacuum switch from a mid-80s vintage Grand Wagoneer. They used a vacuum switch to go from AWB to locked 4WD.

Wrong. If you're not swapping the engine, you should stick with the clutch pressure plate that fits your year engine. You may need to get the clutch disc that has the correct spline count for the 3550 transmission.

That vintage Wagoneer or Cherokee (which is what I had) were considered full-time 4WD, not AWD. The front hubs are indeed like a Warn selectable, without the selector knob. Very easy to work on, and Mile Marker used to sell a kit to convert those vehicles to "normal" 4WD. The kits included the parts to convert the front hubs to selectables, so I'm sure you can do it. FWIW, Clayton (of Clayton's Offroad in Waterbury, Connecticut) has been stuffing those axles under XJs for members of his club for a number of years. I believe he has a kit out with all the brackets and hardware you need to do the front axle. It might be worth a phone call. (Sorry, I don't have the new phone number. His shop used to be just down the road from my brother, but they moved to Waterbury about a year ago and I lost contact.)

Don't have a clue. I assume they used a version with the correct length and spline count on the input shaft. I know for a fact they used the T-5, because my friend in Greece has an '84 XJ 4-banger that was imported to Greece from the U.S. and it has a T-5 transmission in it.

Because someday, somewhere, some Comanche owner is going to need them. Some of us are into MJs to see how badly we can mangle them. Other of us (cough, cough) are into restoring and preserving them.

AMC used the T-4/T-5 and the AX-4/AX-5 interchangably in the first couple of years of production. The specs call for the AX-4/AX-5, but when they ran low on trannies they pulled T-4s or T-5s from other production lines and used them in the XJ (and '86 MJ, rarely). They will interchange. But ... those trannies were used only with the '84 thru '86 2.8L V6. If the tranny you found is behind a 4.0L in-line 6, then (a) it won't fit your 2.5L (directly); and (B) it's not a T-4/T-5 or an AX-4/AX-5. Those trannies were not used behind the I6.

Do you know what engine and transmission were in the truck? It seems unlikely that it would have been a 3.55. That ratio was used only behind early 4-cylinder 4-speeds. It's more likely to be a 3.73 or a 4.10. (I think).

I'm having a hard time visualizing just where it snapped. Was the shock double-nutted? Was it only the threaded portion that snapped off? It looks like you also lost a portion of the actual solid post that the bushing rides on. It also appears that the remaining post is NOT long enough to fully support a bushing if you were to just clean up and square off the end, and weld a threaded stud onto it. Whatever you do, PLEASE don't carve up your old spring plate/shock mount. By pure coincidence (have I mentioned previously that I don't believe in coincidence?), I happen to have an old bag of Monroe supplemental hardware that consists of a complete replacement stud assembly. I will gladly send it to you in exchange for your promise to retain the old lower mounts in stock form, just in case some other MJer needs one in the future. The Monroe stud has an oversized head, that could be ground flat and welded to your frame, or there may be a better way to use it but it's about 12 degrees at the moment and I am not about to go crawl under mine to figure out what that better way might be. I don't have a scanner but if you have access to a fax, I can fax the diagram off the package and sent it to you. You can use that to determine if this thingie might be what you need. Lemme know by PM.

The u-joint is the same, but the pinion snout on the 8.25 is about 5/8" longer than the D35 so you may have to shorten your driveshaft.

The ZJ front axle will bolt into your MJ but, as noted, it's a low pinion. That wouldn't matter at stock height, but it magnifies u-joint angularity issues if you lift. BUT ... it will be a non-disconnect axle, and it should have the larger 297 u-joints on the shafts. And you should be able to grab the front driveshaft as a spare. The brakes will be the crappy Chrysler composite rotors that warp if you look at them cross-eyed, so probably the best deal might be just grabbing the axle shafts, and then you could convert your MJ to the larger u-joints and a one-piece shaft w/o disconnect. Do NOT use the ZJ hubs on your MJ -- the knuckles are different, and the hubs do not interchange. A V8 ZJ probably has the aluminum case D44, which isn't really a D44. If there was ever an axle that's WORSE than the D35 ... that's it. It might serve as a donor o=for a rear disc brake conversion on your existing axle, but don't bother putting the ZJ axle into the MJ. The transfer case will be a 23-spline, so it won't mate to your '88 transmission. Also, the early ZJs used a transfer case that didn't lock the driveshafts in the 4-Hi mode. I don't know what year they stopped doing that. If you are even considering adapting that t-case to work in your MJ, be sure to verify which t-case it is, because it may not be worth the effort. Rims will definitely swap right onto the MJ. The steering box is the same, so you could grab that as a spare. And the front coils on a V8 ZJ should be essentially like Up Country coils in an XJ/MJ ... about a 1" lift over stock. That's about it.

My '88 MJ apparently had factory foglights. The switch is on the dashboard. It had no lights when I bought it and I haven't traced the wiring, but there is a relay on the driver's side radiator side brace that doesn't exist on my '88 XJ, so I believe that's where the foglight relay should be.

CO is carbon monoxide. That's not unburned fuel. Hydrocarbons is unburned fuel.

I got dibs on the MJ from "Monster's Ball," but only if I get Halle Berry with it.

If you replace the catalytic converter, you should also replace the O2 sensor, because if the O2 sensor is bad, the amount of unburned stuff going down the pipe will burn out the new cat ASAP. Personally, I would replace the O2 sensor first, and then do the cat if it still fails. If you're fairly certain you need a cat, do the O2 sensor at the same time.

Yeah, Pete, but you are quoting from a write-up about replacing an AX-5 with an AX-15. That means mating the AX-15 to an engine (and crankshaft) that Jeep never mated it to. This thread is about replacing a BA 10/5 with an AX-15. Both of those were 4.0L transmissions, so it's reasonable to think that Jeep has pilot bearings for them to work with the 4.0L engine.

I ran my MJ with 31x10.50s on stock 7" rims for several years and I didn't notice any odd or accelerated tire wear.

Why would you need a pilot bearing from another Jeep? The XJ and MJ were offered with both the BA 10/5 and the AX-15 ... just buy the correct bearing for the tranny and install it.

NOx is usually a product of high combustion temperatures, which can be brought on by a lean-burn condition. What I did NOT see on your list of things replaced is the oxygen sensor. The O2 sensor is a scheduled maintenance item that should be replaced every 80,000 miles. (I use 75,000 as the interval because the multiples are easier to keep track of mentally.) The two most common cause of emissions failure for the 4.0L engine are the O2 sensor, followed by the catalytic converter. [EDIT]Oops ... mis-read your post. So you're okay on NOx but bad on CO. I still wonder when you last replaced the O2 sensor.

The 1984 - 1986 Jeep 2.8L V6 IS a GM 2.8L engine. Any transmission you can find bolted up to a GM 2.8L (or rear-wheel drive 3.1L or 3.4L) engine will bolt up to your Jeep 2.5L engine. The 2.5L was engineered to share the same bell housing-to-block bolt pattern as the GM 2.8L. The only question is whether or not your transfer case will mate up to the transmission.