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December 2007 4x4 Tech Questions - Techline

Posted in How To: Tech Qa on December 1, 2007
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Address your correspondence to:
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 Due to the volume of mail, electronic and otherwise, we cannot respond to every reader, but we do read everything.

Question: I'm building what I like to call my "freak Jeep" with a '69 Chevy chassis shortened 25 inches, '72 Commando tub, '71 Commando front clip that's stretched 4 inches, '90 Chevy TBI engine, and Dana 60s with 4.56:1s.

Where I'm stuck is, I need to run a Turbo 350 tranny due to a handicap I have, but I want to run the Rockwell 221 transfer case that came with the truck due to the low output shaft and short wheelbase. But I don't know how to put them together other than a roll of duct tape and a coat hanger. Help?
Putter in WI

Answer: Actually, I think that the transfer case was a Timken Model T-221. Either way, it never came hooked to an automatic, only to the SM330 heavy-duty fully synchromesh three-speed manual and the CH465 four-speed. Too bad you're starting out with a '69 instead of a '70, as that was the year of the auto shifter introduction, along with the NP205 transfer case.

I think that you should just forget about using the T-221, as parts for it are getting quite scarce and it's fairly noisy. OK, it's been a long, long time since I last looked at one, but if memory serves me right, it uses a coupler very similar to the 205's. There is a chance that the TH350/NP205 adapter may be modified to work. OK, now that I have said that, I will most likely get a bunch of mail telling me either no way, or it's a bolt-up. Still, I would suggest finding a 205/350 combination already mated together.

Question: I am looking for the meanest, biggest, and baddest grilleguard/winch bumper I can find to put on my '07 Ford Excursion. Can you point me in the right direction?
Jim Buck
Little Rock, AR

Answer: One company that comes to mind (mainly because I received a catalog in today's mail) is Winch Ready Bumpers ( Apparently, you haven't looked too hard into finding one because they have a dealer right in your hometown. Check out Mud Connection 4x4, 6104 Young Rd., Little Rock, AR 72209, 501/562-6494.

Question: I have noticed a lot of ads for electric superchargers. They appear to be 12-volt blower motors that you hook up to your intake tube that sells for around $70.

I have a '92 K-5 Blazer 5.7L that needs more get-up-and-go. Will this device help at all?
David Tagg
Saint Cloud, FL

Answer: Contributing Editor Jimmy Nylund and I have talked on several occasions about these small fans and just how many you would have to put in the air tube to show a difference in power output on a chassis dyno. In reality, there is a good chance that there may actually be an air restriction, even with it running. Then there is the question of what would happen if one of those little blades came off.

What is making the fan work? Electricity, and where does that electricity come from? The engine driving the alternator. If there was any gain in horsepower from the little fan, our guess is that gain would be taken away by the extra load on the engine driving the alternator.

Our opinion: save your money and invest in a good exhaust system. Even if it doesn't make any more horsepower, the engine will run a bit cooler and sound a lot better than a fan sounding like a bumble bee.

Question: I have a '62 Willys CJ-5, which is cool to drive but it is slow and rough-riding. What kind of options do I have to make it more driver-friendly?

Can I take my body and graft it to a Wrangler frame and drivetrain? I'd like to dump all my old drivetrain but can't afford Dynatrac 60s front and rear.

What options can you share with me? What kind of donor drivetrains can work?
Roger Christensen
West Haven, UT

Answer: Well, there are a couple of reasons that your CJ-5 rides rough. The wheelbase is 80 inches and the springs are very short and stiff and most likely pretty much worn out to the point where every little bump puts the axle on the bumpstop. As to being slow, well, the four-cylinder engine only puts out about 75 hp, and the 5.38:1 axle gearing pretty much limits top speed to the 60 mph range.

Now with that said, let's compare it to a leaf-sprung Wrangler, which has a wheelbase of about 94 inches. To start with, you would have to apply a "stretcher" to the CJ's body for it to fit. Fourteen inches is a lot of stretching. Even at that, you would find many other differences in frame design, clutch and brake pedal location, and the like that would make a body swap pretty difficult.

As to the springs, the Wrangler YJ springs are much longer and wider than those on the CJ-5, which definitely makes for better ride quality. So, the Wrangler springs can be adapted to fit the CJ-5 with some special spring mounts and some modifications to the frame.

To even make it better, reverse the shackles on the front springs-that is, put the solid mount up front and the shackle at the rear of the spring. This allows the axle to slightly move rearward upon making contact with a solid object. I believe that Mountain Off Road Enterprises (970/625 0500, has the pieces that can be made to work.

As to power, the Wrangler TJ came with either-depending on the year-a much more modern and powerful four-cylinder, the long-running 258ci six, or the 4.0L six. So this brings up engine swaps. There is not much point of putting in another four-cylinder. The inline sixes are possible, but their length doesn't make for a practical swap. Popular swaps for the early CJs used to be the carbureted Buick 225 V-6, but age has caught up with availability. So that leaves the Chevy V-8 and V-6 swaps, which are common and quite doable.

OK, you could swap out the complete drivetrain, engine, transmission, transfer case, and rearend, which a lot of people do. Maybe if you found a YJ that had been wrecked, body-wise, but the running gear was still salvageable, it would make for a good candidate. But before you lay out the cash for an engine swap, consider adding an overdrive. Herm the Overdrive Guy ( offers rebuilt used Warn overdrives. Advance Adapters ( has the new reproduction of the same unit under the Saturn name. As it can be used in all the gears, even low-range four-wheel drive, it turns your three-speed trans into a six-speed and in effect changes your final drive ratio from the previously mentioned 5.38:1 into the 4.10:1 range. Besides that, it's fun to shift that many times!

Question: I'm 17 years old and I bought myself an ex-Forest Service K-20 Suburban with a 305, TH400, and NP203 combination for plowing. My NP203 already has a part-time kit installed but I would like to replace it with an NP205. Would I need an adapter to make it fit with the TH400, or does it just bolt right up? How much would a used NP205 be at a local salvage yard?
Alex Holt
Redondo Beach, CA

Answer: Yes, you're going to need a new adapter to mate the 205 to the TH400 transmission. You're also going to need a 205 that came from a TH400 transmission, as the input gear has to be 32-spline, not the 27-spline version of the TH350 or the 10-spline version of the SM465 manual transmission.

Price of the transfer case? Depends on how good of a "wheeler dealer" you are and even the particular salvage yard. The adapter needed will most likely equal the price of the transfer case.

Take a look at There is some really good information on this Web site on transfer case selection, as well as other stuff that will apply to your Suburban. You might also want to consider instead of just a 205 swap to do the doubler transfer-case conversion. This will give you some great variability in low-range gearing.

Question: Well, first my water pump went out, so I replaced it. Then about a week later, my motor mount tore through its bolts and my motor fell into my radiator. After I put in a new radiator, it was running hot so I replaced my thermostat and thermostat housing, which broke during the repair. This still didn't make it run right, so I replaced my fan clutch, fearing it could have been broken in the fall. Still it won't run right.

The problem is: at idle, it heats up fast and runs very hot, but hasn't overheated yet, but when I bring it up to about 20 mph, it cools down to almost normal temperature and stays there until the next time I stop-then it heats up again. So I have replaced the radiator, water pump, thermostat, thermostat housing, a couple hoses, and the fan clutch, and it still runs hot. What should I look at fixing next? I'm out of ideas.
Tyler Jenner

Answer: The known facts are: The water pump, fan housing, thermostat, hoses, and radiator have been replaced.

It gets hot at idle.

It runs cool going down the road (better airflow through the radiator and more water-pump speed).

Unknown facts are: What is the vehicle? Some vehicles have more of an overheating problem than others.

Is something blocking the airflow through the radiator? Winch, lights, grilleguard?

Is the belt slipping, or is the clutch fan locking up? Look for signs of glazing on the belt. The clutch fan should be hard to turn by hand when it has heated up. (Naturally, with the engine stopped.)

Is there a fan shroud in place? Perhaps it was damaged when the fan went into the radiator. Without a shroud, the fan finds it easier to pull air from the sides instead of through the radiator. The fan blade tips should be about half in and half out of the shroud.

Condition of the engine: Does it have so many miles on it that it is ready for a rebuild? Did it overheat and possibly be damaged? Is there a restriction in the exhaust system such as a plugged catalytic converter, or smashed tailpipe?

Was the thermostat installed in the proper direction? The "pellet" end goes into the engine block. I have seen people install them backwards before with no end of heating problems.

Is something obstructing the airflow out of the engine compartment? See this month's "Willie's Workbench" for more on this.

Question: I have a '90 Jeep Cherokee Limited 4.0L automatic. I recently purchased a 4 1/2-inch Rough Country lift. Everything I have read recommends a slip-yoke eliminator if you plan to do any wheelin', and I plan to do that every chance I get. Now the only problem is that I can't afford a slip-yoke eliminator. Is there another transfer case that does not have a slip-yoke that I could bolt up to it that could be found at a local junkyard? Or do you know of another low-cost solution to this problem?
Jordan Trompler
Kenmore, WA

Answer: Yes, most likely you're going to have to go to a slip-yoke eliminator kit, as a 4.5-inch lift puts the rear driveline at a just-marginal angle, as well as not quite enough slip-yoke engagement into the transfer case. The eliminator kit will give you more distance between the transfer-case output and the rearend for a longer driveshaft and will result in a better driveline angle. Then you can probably get rid of the spacers that came with the kit to lower the transfer case. This will put the front driveshaft angle back to where it is supposed to be.

There is not another transfer case you can swap to without some major expense. There are some NV231/241 Dodge combinations that use a flanged output, but these would require an input-shaft change along with new driveshafts.

The easiest solution is to do some trading for a 3-inch lift kit. Besides that, I feel that 4.5 inches of lift puts the front control arms at too steep an angle and destroys ride quality. Plus it transfers a lot more load when hitting a rock with a front tire into the arm's unibody mounting point.

Question: I have a divorced NP205 out of a '73 Ford High-Boy. When I pulled it out, I noticed that it had a little bit of slop in it. I have since been looking for a rebuild kit, but so far have only been able to find one for a non-divorced case. I know I am not the only one with this problem with this tough little transfer case. Is there any company that you guys know of that offers such a kit?
Trafalgar, IN

Answer: Well, a lot of the parts and gaskets are going to be the same. Naturally, you're going to have a different input shaft than a direct-mount 205 will have. I suggest that you give the sales/customer service guys at Motive Gear a call at 800/934-2727. While they don't sell direct to the consumer, they can direct you to a dealer in your area.

Question: I have a '79 Jeep Cherokee Chief with an AMC 360, Turbo 400 tranny, and Quadra-Trac transfer case. The problem is in the transfer case, which I have heard is junk. Do you know of any other case that would bolt in? I can't find hardly any information on this truck anywhere.
Don Jones

Answer: To be honest with you, I don't think that the original Quadra-Trac system was all that bad. It was kind of the forerunner of the modern aluminum chaindriven case such as the NP231. It was used by Jeep behind the TH400 from '73 to '79 in two versions: The 13-05, without a low range, and the 13-39 with a 2.57:1 low-range. They do have a somewhat troublesome vacuum-operated locking feature. Jeep realized this and offered a manual-shift replacement kit, but it's long out of the system. It shouldn't be too hard to make some manual linkage, though. I believe Crown Automotive still offers rebuild kits and assorted parts that are available through most shops that sell Jeep parts, such as 4 Wheel Drive Hardware ( or Collins Brothers.

Most likely, it will be a lot cheaper to rebuild the unit instead of swapping it out. Due to the offset output for the rear, the only other transfer case with this offset is the Dana 18. Novak Conversions ( offers a special adapter that cocks the transfer case to the proper angle.

I have seen people use the Dana 20 or Dana 300 transfer case with the centered output, and let the rear driveshaft run at an angle to the rearend, but again this will require a new adapter to the transmission.

Question: I own an '06 Chevy Silverado two-wheel drive with the 4.3L V-6. Where are the headers for this engine? I have been looking around for a little while, and I can find headers for the 4.3 S-10, but not the Silverado. Is this because the S-10 headers will also work on the Silverado, or is it that there really is no market for the Silverado? I can probably have them made, but at a price. I really want to wake my truck up a little here and there since it has the factory 3.23:1 rear axle. Any direction on this would be greatly appreciated.
Adam Woodruff
New Preston, CT

Answer: Both JBA (800/830-3377, and Gibson Performance (800/528-3044, offer headers for your truck. Both companies make some pretty strong claims as to the performance gain which I am a bit apprehensive to repeat here. In the real world, I wouldn't expect that much.

I think that if it was my truck and I was looking for a big jump in performance, I would spend the money on a gear swap. Being only a two-wheel-drive truck, the expense wouldn't be all that much, and the performance gain would be substantial. Most likely there would, however, be a drop in fuel economy.

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