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June 2006 4x4 Tech Questions - Techline

Posted June 1, 2006

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Techline
Four Wheeler
6420 Wilshire Blvd.
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 www.fourwheeler.com. Due to the volume of mail, electronic and otherwise, we cannot respond to every reader, but we do read everything.

Question: What do I do for stronger axles? I have an '01 Dodge Ram 1500 4x4 that I have lifted, using a 5-inch Skyjacker suspension and a 3-inch body lift. I am running 38.5-15.50/16 Boggers. The stock axles are the full-floating Dana 44 in front and the Chrysler 9.25 in the rear. They both have 4.10:1 gears in them. I want to upgrade the axles to handle the 38s, possibly up to a 40-inch tire. What is your recommendation, and where should I shop?
Daron Pope
via fourwheeler.com

Answer: Wow, there are lots of ways to upgrade, but a lot depends on how hard you're going to work those 40-inch tires. If you're planning to really abuse your truck, then maybe you should contact some of our advertisers that build custom axles and have a couple built.

Or you could always hit the wrecking yards and pull the axles out of a 1-ton pickup, which are quite strong and, as long as you're not too aggressive, should handle those 40s fine. These would just more or less bolt in. That way, you will be getting a Dana 60 front and a Dana 70 or Dana 80 rear. You're going to want to change the gears to something like a 4.89:1 gear ratio.

Question: I own a '90 Ford F-150 with a 302, five-speed manual, and lockers front and rear. With the recent trend of superchargers and turbos, I'd like to jump on that bandwagon. I had thought about building a stroker, but with gas prices skyrocketing, I figured that forced induction would perhaps be a better option. So, could I get an engine from a 4x2 F-150 Lightning and transplant it into my 4x4 with minimal modification? Also, what else would need to be changed? Can I just swap the engine and computer, or will the wiring harness need to be changed, too? Finally, does the donor truck have to be a manual transmission, or does it even matter? I'm not sure if the engine computer also controls the automatic trans or if it has its own separate computer.
Name withheld
via fourwheeler.com

Answer: As soon as I read your letter, I knew that this was going to be a difficult swap to perform. The first thing that came to my mind was, "Just where in the heck does this guy plan to find one of these low-production Lightning trucks to pull the engine out of?"

Just for fun, I decided to look into the feasibility of such an engine swap. I gave longtime friend and master Ford Service Tech Mike Kelly a shout and here is what he had to say:"My beloved Ford loves to complicate things. Ford's 'modular' engine family, as they call it, consists of a 4.2 V-6, 4.6 and 5.4 V-8s in two- and four-cam versions, and a 6.8 V-10.They all share the same bellhousing pattern with each other, but it is different than anything else that Ford has made.

"As far as an engine swap for a Lightning 5.4 SC, Ford itself doesn't make any type of a conversion harness that I know of. A person would have to build one themselves or have it built. Perhaps one of the aftermarket folks may make something by now. The 5.4 supercharged engine uses a separate coolant system for the intercooler which has its own reservoir, electric water pump, and mini-radiator. That is just one of the systems you would have to swap over or fabricate.

"So basically it means you can't use your present transmission but would have to use the one that came with the Lightning engine and then adapt a transfer case to it. The intercooler system would take a lot of custom fabrication to make it work properly.

"Then we come to the wiring. Trying to make up the new wiring harness is going to be, well, to say the least, a nightmare. You're going to need complete factory-style wiring diagrams for both trucks along with a good-no, make that great-understanding of automotive electrical wiring systems. Unless you have a good contact at your local dealer who will photocopy them for you, you're also going to need factory service manuals which are fairly expensive and available from Helm (800/722-4356, www.helminc.com). There are so many things in the wiring harness that need to be dealt with, such as cruise control, A/C , gas-tank pressure sensor, fuel-pump drive module, and others. There is even the antitheft system to work around.

"Then you have the computer compatibility issue. Most likely at a minimum it will have to be reflashed to match the weight and driving characteristics of your truck. My guess is that it will take an all-new system to make it all work right.

"Now, there are a couple of places that I can think of that may be able to help you with all this: Motec Systems USA (714/897-6804 www.motec.com) or Link USA (949/636-7461, www.link-electro-usa.com). Be prepared to spend almost as much money as the engine cost you for a custom wiring harness and the hardware to run it all.

"When it all comes down to the bottom line, I think that you definitely would be better off rebuilding your present engine and going with one of the aftermarket supercharger kits that are available for it."

Question: I've been looking at options on replacing the front disconnect axle in my '87 Ramcharger. I looked at the 4x4 Posi-Lok and was wondering if you could help me to see if there are any other solutions? I'd like to just have manual-locking hubs but am unsure about the best ways to go about this.
Bill Wilter
via fourwheeler.com

Answer: As I remember, you should be able to just bolt on a set of front locking hubs. This will allow the wheels, with the hubs in the unlocked position, to just spin on the spindle and not turn the differential gears or the front driveshaft.

For the axle-disconnect system, you could use a Posi-Lok kit to eliminate the trouble-plagued vacuum motor, or you could rig up some way to hold the shift fork so that the locking collar holds both axle halves together. Then again, having the 4x4 Posi-Lok along with the front hubs would give you a wide range of options.

Question: My question is for a '96 4x4 Tacoma extended-cab four-cylinder. I had a 3-inch Fabtech suspension lift put on recently. I have 31x10.50R15s on the original Enkei wheels that came with it. I would like to put 33x12.50s on them. Can I mount them on these wheels? In your experience, do you foresee any rubbing taking place? The current wheels are positively offset right now, and I'm afraid I'll probably have to get new ones to accommodate the tires. How big can I go on these wheels?
Mike Zopfi
via fourwheeler.com

Answer: A lot depends on the width and the backspacing of the present wheels, the information for which you did not supply. Guidelines for a 33x12.50 are for an 8.5- to a 10-inch rim width. Eight inches is not a real problem, but any narrower and the tire has a tendency to "crown"-that is, the center of the tire pushes up slightly, and this will cause more center tire wear. I suggest that if the present wheels are at least 8 inches wide, then mount one tire on it and try it up front and see if there are any clearance issues.

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