Eagle

Mea culpa.

That's because there ain't no other 4.0L, AX-15 ZJs out there. That's almost as rare a bird as my 2000 XJ 4.0L with 5-speed.

It could be bad synchronizers. Does it sometimes pop out of gear when you're coasting? By the way -- did you swap the transmission? Because an '88 should have a BA 10/5, not an AX-15.

Don, you had your stroker dynoed, didn't you? Do you have a torque curve for it? Is it possible that you might do better around town if you put the shifter in "3" to lock out overdrive? If that would put your RPMs closer to the torque peak, it might make a difference.

Incipient CPS failure. I had that in an XJ (the original '88) a number of years ago. Had been running fine. Drove a few miles from a Subway restaurant down the road to Walmart. Noticed a skip under power on the highway, but no other issues. came out of Wally World and it was dead as a doornail. Another possibility is failing spark plug wires but, with a Jeep 4.0L, I now tend to suspect the CPS before I look at ignition wires.

Using the rotary switch takes care of that. It only locks it in third or fourth, and the shift from third up goes to UNLOCKED fourth. Then it's another switch position to lock it in fourth.

Don't know if it matters, but what year? Torque specs sometimes changed from year to year.

I don't know how Frank did it, but he did it. It was his daily driver, I believe. And I'm quite certain he was using a rotary switch. I remember because at the time I thought it was a terrific solution. Since I'm not an electrical engineer, don't know protected diodes from unprotected (first time I ever heard of protected diodes), and don't know what "iso" is, I'm afraid I can't offer anything useful other than the concept (which isn't mine).

When you shift manually, you lose first gear. Frank did it with a rotary switch. That made it progressive -- just move one position for each gear you want. I believe he said he used a six position switch. The way I think that would play out would be: First Second Third Third - locked Fourth Fourth - locked

I have a question that I've often wondered about, but never pursued since I mostly drive standard transmissions: Exactly how does an automatic tranny shift? If you add a toggle switch to control torque converter lockup on the AW4, can the tranny shift from fourth to third or second with the converter locked (as long as you're moving at an appropriate speed)?

Back in pre-NAXJA days, on the old XJ forum, Frank Swigert posted details of how he wired an AW4 with a rotary switch in an AMC Hornet. Someone on the strokers forum may know how to contact Frank -- I believe he's still around.

Only "sort of " close. 31x10.50-15s through 3.73 gears are almost exactly equal to 225/75-15s through 3.55 gears.

Add a toggle switch to manually control torque converter lock.

Agreed. Two things that terrify me are spiders and snakes.

You'll probably get better fuel economy, too. I recently did a 200 mile road trip in my 2000 XJ 5-speed. I had to keep the speed below 65 MPH due to a tire balance issue -- I got 20.4 MPG. When my '88 XJ 5-speed was a couple of years old, I once got 28 MPG on a trip from Connecticut to Vermont -- with a girlfriend, two kids, and everything that entourage required for a long weekend.

Yes, it does matter. At least on the Renix models. That's why the factory issued a TSB on "indexing" the distributor.

The distributor is driven by the camshaft. Retard the camshaft and you retard the spark. Or, at least, you retard where the distributor rotor is relative to the turrets in the cap. And don't forget that there's a distributor sensor involved as well as a CPS.

The problem is, without comparative dynomometer runs on the same engine and same camshaft with both chains ... how are you going to know? It's going to run. I think you'll have to have a very sensitive "seat of the pants dyno" to pick up on the difference, and if you're dropping a different engine into your truck, any perceived difference could be due to the cam timing, or to other factors. The factory did make some changes but, of course, the parts manual doesn't tell us what the differences are, only that there are different part numbers. 87-93 . . . . Chain . . . . 3300 2977 . . . . . . . . . .Sprocket . 3300 2978 94-99 . . . . Chain . . . . 5302 0444 . . . . . . . . . .Sprocket . 5302 0445 2000 . . . . Chain . . . . 5302 0444 . . . . . . . . . .Sprocket . 5301 0400 2001 . . . . Chain . . . . 5302 0444 . . . . . . . . . .Sprocket . 53010 557AA

I always hoped he'd still be there the next time I made a road trip to the western U.S. I guess I waited too long, and that's my loss. Jim was a great resource for the Comanche Club and he will be missed by all who knew him, whether in person or only through cyberspace.

That was pretty much my assessment. "Better than nothing."

Looking at your photo, it appears that both brake shoes have the same length lining. Usually there are two with long linings and two with shorter linings. They get paired, one long and one short per side. The short lining goes toward the front of the vehicle.

The solenoids are the key. Back in the days of the old XJ Forum (the predecessor of NAXJA) there was a member named (IIRC) Frank Swigert who had an XJ 4.9L engine and AW4 transmission in a Hornet station wagon. He had the tranny wired up to a 6-position rotary switch so he could control shifting manually just by turning the knob. Once he had it in overdrive (4th gear), the next step on the knob locked the torque converter. That's why the FSM for the AW4 starts out by having you pull the fuse for the TCU and test drive by shifting manually. If that works, the tranny works, and you look for electrical problems.

No, the peddle doesn't stay depressed ... but the front bleed screw remains open. Obviously, if you're bleeding the traditional way (by having one person open and close the bleeder while a second person alternately depresses and releases the brake peddle) the peddle can't stay depressed. The purpose of opening a front bleed screw is only to simulate a failure of the front brake circuit (loss of pressure) and to trip the shuttle valve. If the shuttle valve doesn't move, the bypass circuit doesn't open and you can't bleed the bypass circuit.

Not certain, but I don't think the vacuum pump can bleed the bypass circuit. The reason for the special procedure is that the MJ has two brake lines to the rear. The primary goes through the rear load/height sensing proportioning valve. The secondary line is a bypass, so that if you lose the front brakes you'll get full braking to the rear, not "proportioned" braking. The bypass circuit isn't open unless the shuttle valve in the front distribution block has been tripped. That's why the FSM calls for opening a front bleeder and stepping on the brakes. The idea is to simulate a front brake circuit failure. If you didn't step on the brakes hard enough with the bleeder open, perhaps you didn't trip the shuttle valve. Also, the fact that your brake warning light on the dash illuminates doesn't mean the switch at the distribution block is working. Here's what the distribution block looks like, with the bypass circuit opened by tripping the shuttle valve: That pastic thingie on top is the switch that activates the warning light. Normally the plunger rests in that notch, which is the OFF position. When it moves to either side (depending on whether the front or rear circuit fails), the plunger is pushed up and the light goes on. If you didn't trip the plunger, the bypass circuit would be closed and the suction bleeder wouldn't pull anything through the bypass circuit. Even with the plunger tripped, I don't know how effectively the vacuum bleeder would get the bypass circuit, since the primary circuit is also open. I use a vacuum bleeder on XJs, buty I still use the foot pedal when bleeding MJs.