Eagle

Are you trying third and overdrive on the road, at legal speeds, or from a standstill in the driveway? Don't forget, if you're trying to test it while parked in the driveway it's the same as trying to start up a vehicle with a manual transmission in fifth gear. Not recommended. One of the troubleshooting routines for the AW4 is to remove the fuse and drive it by shifting manually. That should work -- except there's no second gear. If you can drive it like that, you may need a transmission control box.

I hope by revealing that insider information I am not contributing to the wholesale destruction of a bunch of MJ steering boxes. The box in my '88 MJ had an incredible amount of slop in it when I bought it. When I investigated to see if it could be adjusted out, I found that the adjusting screw was already TIGHTLY bottomed out -- which meant the idiot kid who had gotten the truck from his grandfather (the original purchaser) had tried to make it as tight as a rack-and-pinion steering gear and, instead, ruined it. I had to replace the box. The fact is, they rarely need to be adjusted. My '88 Cherokee has gone 287,000+ miles and the steering box is still tight. DON'T GO CRAZY.

Yes it is. ALL Comanches used GM Saginaw steering boxes, and they ALL adjust like that.

The valve cover.

Did you check the U-joints while you had the drive shaft out?

You don't have an AX-15, you have an AX-5 -- you know that, right? All AMC engines 1970 and newer will accept the Jeep 4.0L bell housing and AX-15 transmission. They are all the same basic block, and a friend bolted one behind a 390 in a street rod, so I know it works.

That video is good for showing you what to adjust and where, but lousy for explaining the actual process. He does mention that overtightening can ruin the box, but he doesn't offer any advice as to how to avoid overtightening. The first thing is, especially for you young guys who grew up driving foreign cars with rack-and-pinion steering, is that the Jeep steering is NOT rack-and-pinion, and you can NEVER make it as tight or as precise as rack-and-pinion. If that's what you're aiming for -- you WILL ruin your steering box. That "stud" (as he calls it, which isn't a stud but a screw with a locknut) is the "over-center lash adjustment screw." The Jeep steering box is what is called a "worm and ball" steering box. There has to be a certain (very small) amount of backlash or free play to allow the parts to work without undue wear -- exactly as the differential requires a small amount of backlash between the ring gear and the pinion gear. In the steering box, the geometry of the gears and threaded input shaft are such that the backlash is least when the steering box (and road wheels) are stright ahead, and there's more lash when the steering is off-center. So ... first thing, ONLY adjust the over-center screw when the steering wheel is centered in the straight ahead position. Next -- how to know when to STOP adjusting. Basically, by feel. Set the steering wheel straight, then leave the key in the UNlocked position so you can turn the steering wheel with the engine off. Stand outside the vehicle so you can visually align a fender or flare edge with a point on the tire tread or shoulder. Now, reach in and wiggle the steering wheel back and forth. Don't try to turn the tire, just see how far left and right you can move the wheel before you can see ANY movement whatsoever at the tire. That's your over-center lash, or free play. The goal is to adjust almost all of that free play out, but leave just a tiny bit so the steering doesn't bind up across the center. As I said above, I do it by feel. Once you have the locknut loosened and the Allen (hex) key in the adjusting screw, lean down and grab the collar where the steering shaft connects to the steering box input shft with your right hand, and the Allen wrench with your left hand. GENTLY wiggle the steering shaft back and forth. You should be able to feel if there's a range through which it rotates freely before encountering resistance. While you wiggle the shaft, turn the Allen wrench slowly. You'll feel the range of free play decreasing. Keep going until the free play seems to just about reach zero, then back off perhaps 1/8 of a turn. Use the Allen wrench to hold the adjusting screw at that position while you tighten the lock nut. Double check to verify that you still have a very small amount of free play (lash). If not, loosen the lcoknut and back off the adjusting screw another 1/8 of a turn.

28 to 30 is good.

I have had the same thing on damp mornings, but I don't attribute it to "flash rust" -- whatever that is. I think it's because the lining material absorbs moisture and swells up. This makes the brakes, particularly the rears which have a self-applying "servo-assist" feature, highly sensitive until a couple of stops dries out the moisture.

Ya know, I thought my wife's was a 4-row, but looking at Don's photo ... I'll bet hers is the exact same unit. But SHEESH! $250?

It's big! I looked at a trans cooler that Auto Zone in my area keeps in stock, and it was tiny -- about 2-1/2 inches high and I'd guess not more than 6 inches long. It's a 2-row, and smaller than OEM. The OEM cooler in my wife's XJ is a 4-row (yours is a 6-row), about 4 or maybe 5 inches high and 15 inches long. I don't see much need to go bigger than that, considering that 90% or more of the XJs and MJs ever built with automatics had NO external tranny cooler.

How old is the CPS?

I guess it's time for a radiator. The old one doesn't owe you anything -- my '88 XJ is on its third radiator.

No, the distributor will NOT work. You'll have to use the '88 distributor. Setting both engines at TDC is the ONLY way to make this work. And don't forget these are 4-stroke engines -- each cylinder hits TDC twice for a complete intake-compression-power-exhaust cycle. Both engines have to be at TDC in the compression stroke.

Correct. Now ... if the problem is pinging, and it's a Renix vehicle, the problem could be a broken knock sensor.

Not off-hand, but why aluminum? Weight really isn't an issue for an MJ, and copper cools better than aluminum.

No, but it can be done. The AMC 20 is the axle that AMC used under all the V8 Javelins and AMXs, from the 290 all that way up to the 401. I used to race with guys who ran VERY built 390 AMXs with basically stock AMC 20 axles. Some even ran the factory limited slip, others went with Detroit Lockers. Except for one guy who built an AMX (the original, 2-seat version) for pro stock. To fit the size (width) tires he needed without adding external flares, he had to cut out the unibody in the trunk, weld in a custom-made, narrowed sub-frame, and shorten the axles several inches on each side. That was a very long time ago and I don't know if I ever knew exactly how he shortened the axles. If I knew once, I sure don't remember now. But it can be done and has been done.

I agree it'll run better if tuned right. Do you think you can set the timing better than the computer? You already discovered that the distributor cannot be adjusted. Why are you surprised to have it confirmed that the timing is not user adjustable?

That's correct. Timing is controlled by the ECU.

Okay, then on to my next question: Are you over-filling the plastic bottle?

The 304 was completely emasculated compared to the 290 that preceded it, even in 1970 (which was the first year for the 304). The good news is that the 360 (and the 390 and 401) are externally exactly the same engine, so it's no more (or less!) work to fit a 360 into an XJ or MJ than it is for a 304. I had a 360 2-barrel in my 1978 full-size Cherokee and it was a VERY strong engine. My brother also had a '78 Cherokee, but his had the 4-barrel version. It was a torque monster. What severely limits the 304 is the valves are too small. The 360, 390 and 401 have MUCH larger valves. I'd have to go find my copy of the old AMC "Go Fast Book" but my fuzzy recollection is you can't just bolt on 360 heads because the smaller cylinders won't allow the valves to open. Interference fit, and all that. But that doesn't mean you can't do a bunch of head work, porting and polishing, and perhaps fit in slightly oversized valves, to free up the airflow a bit. And torque at low RPM doesn't require as much air flow as high RPM horsepower anyway, so combine some head work with a good RV or torquer camshaft and you could be on your way.

It's not. Pete isn't kidding about cooling issues.

If it's boiling over, how do you know it holds pressure? I don't know any way to test those plastic caps. Another thought: How full are you filling that bottle? It should be filled halfway when cold. Because there is no expansion bottle, it needs that air space at the top for coolant expansion. If you have been filling the plastic bottle to the top, that's whay it has been boiling over. The only effective way to test a radiator is to remove it from the vehicle and take it to a radiator shop to be pressure and flow tested.

There isn't much point to doing anything until you know what the cause of the problem is. It's an '88 4.0L, so it should have the plastic coolant tank on the firewall (passenger side). If it's boiling over, that's where it will boil out. Is the tank cracked? Does the cap hold pressure? That tank isn't an "overflow" tank on the '88s -- it is part of the pressurized system, and if the plastic cap won't seal to the plastic tank -- the system won't hold pressure and that's often a cause of overheating. Check that first. Do not judge by how hot the hood gets. The hood on my '88 gets too hot to open without risk of burns on a summer day, and my cooling system works fine. Same is true for my wife's 2000 XJ and my 2000 XJ. So I don't consider that to be even a symptom of a problem, but obviously boiling over IS a symptom of a problem. You may need a radiator, and if it's the original radiator in an '88 with idiot lights I would almost bet that ultimately you'll be buying a radiator. But -- check out the pressure bottle first.

Right, but that's only the slider that triggers the brake warning light. If either the front or the rear circuit fails, the pressure differential moves that slider, which then activates the switch (that off-white plastic thing screwed into the top of the metering block). Once the brakes have been repaired and bled, a couple of good, hard stomps on the brakes generally is all that's needed to reset the switch and slider. Doesn't affect the braking. (Except to allow full pressure to the rear circuit if the front brakes fail.) Here's what they look like inside: