Eagle

If it's a 1988 or newer, try bypassing the ballast resistor.

What are the symptoms when it doesn't come on? Does it die when running, or not start, or ...?

See post #1.

It's a 2.5L, so it's throttle body injection. Are those the wires for the injector?

At some point the paint color tag was on the upper radiator brace. I don't remember if that was the "new" position, or the "old" position. There should also be a tag on the driver's door that includes, among other information, the paint code.

One other advantage to the LP Dana 44 is that you can go deeper with gearing. With the Dana 30, the lowest factory ratio was 4.56, and the lowest available from the aftermarket is 4.88. Beyond that, the pinion would get too small.

It's blowing fuses because you are using more current than the fuse can carry. That's what fuses are for -- to prevent the wires from burning up. Did you try any of the trouble-shooting suggestions you've been given?

More like 20+ years. The XJ has been out of production for 13 years.

Early XJs built in Venezuela (for their domestic market) had D44 front axles.

You may like the look of the Waggy grille, but you WON'T like the lighting. Those headlights are smaller than the usual quad headlamps, and they give off about as much light as a single candle on a birthday cake.

Two thoughts, for starters. First, a slight stutter under load is often caused by bad spark plugs and/or bad spark plug wires. Second point is that the early (non-HO) 4.0L engines don't have the same power curve as the new ones. If you haven't yet owned one with a distributor, that means you haven't owned anything older than a 2000 (or maybe a 1999 if you had a Grand Cherokee). The Renix era 4.0L (1987 thru 1990) is not the seat-of-pants rocket ship that the newer ones are. There's a reason why Jeep called the second generation "High Output" when it was introduced in 1991. If you are expecting a Renix-era 4.0L to give you the same seat-of-pants feel as the 2000+ versions ... forget it.

Me too. 3.73s with 31x10.50-15 tires is exactly the same final drive ratio as a stock automatic on 225/75-15 tires. IMHO 4.10s is about optimum for 31" tires. I wouldn't even consider running 33s with 3.55 gears.

^^^ Truth. The RMS for the 2.5L 4-cylinder requires pulling the transmission. The 4.0L 6-cylinder does NOT require pulling the transmission, and doing so will not get him access to the seal. You have to drop the oil pan and remove the rear main bearing cap, and you can't do that just by removing the transmission. I understand that this guy is your friend and he thinks he's doing you a favor, but ... he's not. He obviously doesn't know jack about Comanches, and he's probably going to mess something up dropping the transmission unnecessarily. That means it's going to take him two or three times as long to do the job as he thinks, and on top of that $14 seal you'll still need to buy a new pan gasket. (Hint -- get the '95+ one-piece pan gasket -- it works MUCH better.) Either do it yourself, or take it to a shop that knows how to do it.

If it's blowing fuses, you have a short circuit somewhere. Find the large(-ish) connector where the rear harness plugs into the chassis harness. Unplug it, then try again. If it still blows fuses, that's not the problem area. Then disconnect the front light harness and try again, Rinse and repeat as necessary. You need to isolate the problem to a smaller universe than the entire truck, or you'll drive yourself bonkers just chasing things around because somebody said, 'Try ___."

'87 4.0L 5-speed on stock tires: 3.07 '88 4.0L 5-speed on 31s: 3.73

Unibody. With a full-size truck that sits on a full frame, you can just remove a few cab mounting bolts and pick it up. Unibody doesn't work that way.

Does TrailMaster still exist, and is their drop bracket kit still available? My '88 MJ had a TrailMaster lift with drop brackets when I bought it. I wheeled it like that for several years -- until I got tired of the lift and put it back to stock height. It was a good kit, plenty beefy. I passed it along to Frank the Dog in exchange for his help removing the lift. Looks like TrailMaster is still in business. Their current lift kits don't seem to include drop brackets, so I sent a message to the sales department to ask if they are still available.

I agree. Even in high range the transfer case makes a bit of a whine in 4WD. If you can't tell you're in 4WD fromt that and the shifter position, you should probably be driving something with full-time AWD rather than an MJ.

You can't just swap cabs. The MJ is unibody. The only way you can do it is to swap your entire '91 drive train over to the '86 body -- and that's where you encounter the problem of the '86 firewall not being designed to accept the in-line, 6-cylinder 4.0L engine.

^^^ This.

That's where they run. The purpose is to get the air inlet up high enough, and perhaps facing to the rear, so the intake is above any water or muck that you're likely to encounter.

Is this in the '92 MJ shown in your profile? If so, you have an electronic speedometer, so it isn't the speedo cable. Your profile also says that you are converting to 4x4. Have you done the transfer case swap yet -- or have you had the speedo drive gear out of the transmission for any reason? The reason for asking is that the carrier for the speedo gear has the bore for the gear slightly off-center, and it has to be mounted in a certain position depending on your gear ratio (actually, depending on the number of teeth on the speedo gear). The drive gear is nylon. If it wasn't installed correctly, it may be worn or it may have stripped the teeth.

Ya got me. Brain freeze. The upshift light has been disabled on all my Renix-era vehicles for so long that I forgot. On the 2000 XJs it's located above and to the right of the speedo.

You need to replace the fuse panel. I don't know if synthetic brake fluid is corrosive, but I think it is. DOT-5 silicone brake fluid is not corrosive. It's pricey, but the clutch doesn't use that much.

Rocker mounts on head have not been machined, cam is one step above stock, push rods are stock. Anything I need to concern myself with here? Thanks Cam one step above stock means the base circle is smaller than the factory OEM can. Depending on how much difference there is in lift, your push rods may or may not be okay and the lifters may or may not provide enough range to compensate.