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May 2007 4x4 Tech Questions - Tech Line

Posted in How To: Tech Qa on May 1, 2007 Comment (0)
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Four Wheeler
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Los Angeles, CA 90048-5515.

All letters become the property of Four Wheeler, and we reserve the right to edit them for length, accuracy, and clarity. The editorial department also can be reached through the Web site at Due to the volume of mail, electronic and otherwise, we cannot respond to every reader, but we do read everything.

Question: On your Project Teal-J, you crammed a 5.7L Hemi into that thing. I have a '97 Dakota that is both my daily driver and my toy, and I would like to do a swap. Could you tell me where I could look for a replacement wiring harness like the one that was used/made for the Teal-J?
Erick Andraca

Answer: I don't know-the two vehicles should be somewhat similar, but how close is anyone's guess. Here are some places that have done the Hemi swap into Jeeps. Perhaps they can help you out with the proper wiring harness: Deibel Jeep in Flagstaff, Arizona (928/774-5337,, Burnsville Offroad in Burnsville, Minnesota (952/890-3990,, and Teraflex in Murray, Utah (801/288-2585,

Question: A few months ago, I wrote about seemingly high temperatures for the Ford AOD transmission installed in my '55 Willys Wagon. I appreciate your taking the time to investigate this situation. The situation was resolved by moving the temperature sensor probe from the filter, which is in the cooling line to the transmission oil pan. The reason for the seemingly high temperatures is because the cooling line pumps out "used" transmission fluid directly off of the torque converter, and its temperature depends on the load applied to the vehicle. A more accurate temperature is indicated at the oil pan, which is the source for the transmission fluid that the transmission actually uses. After making this change, the temperatures run between 130 and 180 degrees, which seems much more normal.

Now a quick question, and hopefully a correspondingly easy answer: Why are some aftermarket LED tail-, parking- or stoplight conversion lights not DOT-approved? What criterion must such LEDs meet to be "street legal"?

Thanks for a very helpful column and informative magazine.
Gary Holmes
Concord, CA

Answer: Guess I should have asked where you were reading the temperature. An inline temperature gauge is never very accurate. I always recommend reading the temperature of a fluid, if at all possible, right in the oil sump-or in your case, the transmission pan. This is the important temperature.

As to the lights, my understanding is that they have to be submitted for approval and the testing costs money. Maybe the manufacturer figures he won't sell enough to make it worthwhile. However, I am going to check up on this soon and see if I can get an answer as to the testing involved.

Question: I just got the Feb. '07 issue and thought it was great. However, there are a few problems. The first is from "Techline" about the NP203/205 question. The proper shift pattern is, from front to back: 4-Low Lock, 4-Low, Neutral, 4-High, then 4-High Lock, and not as you described.

The second problem is not really a problem but additional advice from "Willie's Workbench," in that before you drain anything on a vehicle, especially on our type of rigs, is to remove the fill plug, cover, cap, screw, and so forth before draining. This is experience talking. I have personally seen unremovable fill plugs on rear axles and transfer cases and had to make my own fill ports. For those unfortunate enough to not follow this simple-but-maybe-crucial first step in the process, nothing is worse than draining the life blood from your vehicle and not be able to put it back.
Michael Hodge

Answer: Yep, you're right. My own personal proofreader really slipped up on this one. I will banish her to scrubbing my transfer case with a toothbrush for that one. I must have been dreaming of Moab when I wrote that about the shift pattern, or maybe the NV242 conversion for my own Grand Cherokee. On second thought, I should be the one scrubbing the transfer case. Thanks for the catch.

I thought I had turned a lot of wrenches in my time, but I doubt that I have ever come across unremovable fill plugs on a transfer case or rear axle. OK, I assume that you mean fill plugs that are put in so tightly, and are now corroded so badly, that they don't want to come out without a lot of unfriendly persuasion. So your idea of checking the fill plug first just may not be a bad idea. Thanks for the tip.

Question: I have a '95 Ford F-150 shortbed with a 300 straight-six and five-speed. I've already purchased a 6-inch suspension lift and reworked the interior a bit. I want to swap the 300 for a rebuilt 429 big-block with the four-speed. I am not planning on a power-hunting rebuild, just a refreshening of the engine.

1. Can I buy engine mounts for this, or will I need to fabricate them?

2. Will I have to use a different transfer case? If so, will the one I was using behind the 429 work ('79 Bronco transfer case with 351M)?

3. Will I need to get different driveshafts?

If you guys could point me to a Web site or something I'd be eternally grateful! The magazine is fantastic-keep up all of the great work.
Rob Jonesvia

Answer: Sounds like you're building a really nice truck. Sure, there are pre-made motor mounts, and they are available from several sources. One that comes to mind is Advance Adapters (800/350-2223,, which has the proper frame mounts under PN 713224 and the rubber mounts under PN 713014.

To mate the four-speed transmission, you're going to need a bellhousing from one of the same family of engines-the 351M, 400, 429, and 460. I am not sure, from your letter, if you already have the four-speed coupled to the Bronco transfer case (which should be an NP205) with a factory adapter. If not, you're going to be better off if you can find a donor truck that has both the transmission and a 205 transfer case already mated than to buy the transmission and then buy an aftermarket adapter.

Yes, most likely you're going to need new driveshafts of the proper length, especially with the lift that you plan.

Question: How accurate are those electronic readouts that new vehicles use regarding fuel mileage, and how in the heck do they work?
Max Brown

Answer: These readouts have been out for quite some time now, and in fact, my own 11-year-old Grand Cherokee has one that is quite accurate. It was a pretty simple add-on for the vehicle manufacturers. The electronic control module already had most of the information it needed as it adjusted fuel flow to match speed and to measure the miles traveled. It adjusts speed by controlling the time and the width of the fuel pulses from the individual injectors. Some simple and very fast math (well, simple if you're a computer), and you can figure the given amount of fuel that passes through each injector in a given time period under each driving condition. Now it throws in the miles traveled during that time period, and bingo, you have current fuel mileage, average fuel mileage, and miles left on the remaining fuel.

Question: I have a '92 YJ with a tired 4.0L, while in my garage I have a '90 4.2L block that I was thinking about rebuilding. The problem is that I want to keep my fuel injection. I've heard that you can put the head of the 4.0 on the 4.2, but what about the EFI? Isn't there a crank positioning sensor on the 4.0 block?
J Masters

Answer: This is a pretty common swap, and while I haven't had any hands-on experience with it, I have been told it's pretty simple and well worth the effort. It's a basic bolt-on for any 4.2L built before 1981. It seems that the 4.0L head uses 1/2-inch head bolts, and the 4.2s (starting in 1981) use smaller 7/16-inch head bolts. The deal here, as I understand it, is that you have to drill and tap the block for the 1/2-inch bolts, then use the 4.0 head gasket. There are some problems in mounting the 4.2's power-steering pump to the 4.0 head, but with some modifications to the bracket, it seems to work just fine.

For the fuel injection to work properly, you do need a pick-up sensor. You can buy a special bellhousing from Advance Adapters or use a special wiring kit from Hesco (205/251-1472, that uses a new dampener and puts the sensor up front.

I believe that you also have to drill a new hole for the 4.2's temperature sending unit. Oh, and this is really important: The No. 11 bolt in the head-bolt torque pattern requires some type of sealer on the threads as it goes into the water jacket.

Question: I have a '94 Ford Explorer 4x4 with a 4.0L V-6 in it. I want to swap it for a 5.0L V-8. Is there any info that you can give me to help me complete my task, such as things I will have to change, and a list of any and all parts I will need? Do you have a link to anyone who has a conversion kit?
Keith Rhoads

Answer: You're somewhat in luck. The Ranger pickup and the Explorers shared the same frame and drivetrain, and the Ranger V-8 is a fairly popular swap. The first question that you need to ask yourself before taking it on is: Will it be smog-legal when it's all done? The second question: Is it worth the effort? My opinion is that it would be a lot more practical to just jump up to a '97-and-later Explorer that came with the factory V-8.

I don't know of anyone who has a complete conversion kit for such a swap, but check out James Duff (865/938-6696, as well as Advance Adapters. Both of these companies have what you'll need to complete the swap, along with instructions.

Question: I was just wondering if a Dana 44 from an '86 CJ-7 is a good axle for swapping, or is it weaker than the AMC 20 and early Dana 44?
Kevin Barnett

Answer: Well a lot depends on exactly what you're putting the axle in. The flanged axle design is a lot stronger than the tapered axles and hub assembly used on the AMC Model 20 or the earlier Dana 44s. All 44 rear axles take the same differential gears. If it's a replacement for either axle, then, yes, it is a good choice.

If you're going for the flanged axle, keep in mind that there are several companies that offer flanged-axle conversion kits for either of the before-mentioned axles. This may or may not be less expensive than swapping the complete housing out.

Question: I have an '86 Jeep Grand Wagoneer with the AMC 360. I'm about to do a rebuild and want to know if I can take the crank and rods from a 401 and turn my 360 into a stroker motor?
Dusty Luttrull
Gosnell, AR

Answer: Yes, you can, but why not use the complete 390/401 engine for the added cubic inches and more power? The 360/401 combination, by my math (which, by the way, is usually pretty bad), makes for 385 cubic inches with a standard bore and 390 with a 0.030 overbore. I have heard of some motors going even larger and using Chevy 400 pistons with a bit of machine work for 393 cubic inches. However, most machine shops tell me the cylinder walls get mighty thin and distort. Oh, and by the way, the crank and rods of the 390/401 motors are forged, so strength is not an issue here.

You're far better off with the 390/401 block as it has some heavier main bearing support webbing. This makes for a more rigid block and much longer engine life. Besides, if you're going to do a complete rebuild, why not overbore a 401 for even more cubic inches? Reject the '68-'69 motors as they have poor cylinder heads and a bit shorter rod to match the shorter deck height.

I highly recommend an Edelbrock intake manifold. The stocker weighs in at around 56 pounds, and an aluminum unit will flow better, make at least 20 more horsepower, and it's only about half the weight. Now, if you really want to make some power and lose some more weight, go with a set of Edelbrock heads.

The biggest shortcoming of the AMC engine is the oiling system. It uses an external pump that is part of the front timing cover. Since it is made out of aluminum, the pump housing is quite subject to wear, and it doesn't take much to greatly reduce the oil pressure. New housings/covers are available, and I highly recommend that you buy one. Pay close attention to the clearance between the pump's cover plate and the gears. With the proper gasket and/or a bit of milling, you should try for about 0.002 inch of clearance. A couple of Web sites that may offer some suggestions for building your motor are or


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