Techline: Your Top 4x4 and Off-Road Tech Questions Answered HerePosted in How To: Tech Qa on October 24, 2018
Dana 44 InquiryDo you know where to find a cheap used Dana 44 front axle? The gear ratio does not matter.
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When selecting a Dana 44 front axle, or any front axle for that matter, there are many things that need to be considered prior to pulling the trigger on your swap. The most important variables that need to be contemplated are which side your transfer case front output is on, overall axle width, and lug pattern. Of course, gear ratio, suspension type, driveshaft adaptability, brake size, and other elements are important too; however, these are typically smaller details that can be more easily overcome with aftermarket parts and a bit of custom fabrication.
The most common useable Dana 44 front axles with the differential on the passenger side are from ’76-’80 GM 1/2- and 3/4-ton trucks and ’74-’79 Jeep FSJs. The 1/2-ton versions have a 6-on-5.5 lug pattern and the 3/4-ton versions have an 8-on-6.5 lug pattern. The early Dana 44 axles are kind of like a Lego kit. To some degree you can mix and match parts to get the steering knuckles, lug pattern, and brakes that you need for your project.
If you are working with an application that requires a driver-side front differential, your options are more limited. These Dana 44 axles can most commonly be found in the front of ’74-’79 1/2- and 3/4-ton Ford F-series trucks, the ’78-’79 Bronco, and ’80-’91 Jeep FSJs. Of course, there are other applications, but they are less common. The Ford axles have nearly dried up and can be difficult to locate. Unfortunately, most of the larger wrecking yards have vehicles that are 20 years old or younger, so many of these trucks and their parts have long since been scrapped. You can often find many of these adaptable axles in your local classifieds, on Craigslist (craigslist.com), and on eBay (ebay.com).
If you are working with a more modern Jeep (like a JK Wrangler, for example), you’ll be far better off finding a JK Dana 44 to swap in. This axle will have all the correct suspension brackets and will be a direct bolt-in swap in place of the less desirable Dana 30. These axles are extremely common and can be found online and even new in a crate at your local Mopar (mopar.com) dealer. Be wary of used JK front axlehousings that have been abused. Aggressive driving with tire sizes in the neighborhood of 35 inches in diameter or larger can cause the JK axlehousings to bend. Make sure you’re not purchasing an abused, bent used axle when shopping.
Wheel Travel vs. Tire SizeWhat would you rather have—smaller tires and more uptravel, or bigger tires and less uptravel?
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Ultimately, I’d prefer to have both big tires and plenty of suspension uptravel, but given the option of only one or the other, my choice would depend on the type of off-road driving I planned on doing with the 4x4. For off-road travel that requires higher speeds off-road, such as blasting through the desert or even overlanding, I’m going to choose suspension uptravel and smaller tires. Selecting less uptravel and larger tires can be made to work too, but generally not as well. Airing down large tires makes them more compliant, and they can provide quite a bit of secondary suspension travel in the carcass of the tire. However, that motion within the sidewall of the tire is not damped by the shocks, so it can make for a rough ride. For low-speed crawling, the larger tires and less suspension uptravel is a solid choice. The extra ground clearance under the axles provided by the bigger tires will be valuable, especially in riverbeds and on climbs littered with loose boulders just waiting to catch the steering linkages, a driveshaft, or a differential.
Cooler CoolingI have a ’00 Jeep TJ with the 4.0L inline-six and a winch on the front. It’s running warm in traffic on 90-100–degree days with the A/C on. Everything in the cooling system is new except the fan clutch. Heat soaks the injectors occasionally, but not to the point of losing coolant or boiling over. The A/C just starts blowing warm air and the gauge creeps above 210 degrees. It never runs hot while moving at speed. I was thinking of putting louvers on the hood and an auxiliary fan on the condenser. Any ideas?
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Keep in mind that 210 degrees is not overheating in your application. The standard operating temperature for the ’00 4.0L is within 200 to 210 degrees. If it gets to 230 degrees or so, you have a real problem. Unfortunately, the A/C system on the TJ has never been known to be incredibly efficient, especially on extremely hot days. There are a couple of things you can do if you just don’t like the engine running that warm, and these fixes should help the A/C cool down a bit too.
Now, assuming everything was operating normally, and if it was running warm at speeds over 25-30 mph, I’d say you had an airflow problem. This can be caused by aftermarket parts, such as a large bumper, off-road lights, or a winch blocking the airflow through the grille at speed. Mud and bugs can also clog the radiator fins, reducing airflow and potential heat dissipation. It’s not a bad idea to flush out the radiator fins from the engine compartment outward if you regularly encounter mud and large swarms of bugs. However, don’t use a power washer or anything with high water pressure or you could damage the fins. Since you are only noticing the problem at slow speeds, it could be a fan or fan clutch problem. Make sure the fan shroud is in place and not cracked or broken. Also, check that all of the blades are in place on your fan and then test the fan clutch. Sometimes even a worn but still functioning fan clutch can cause the problem you are describing. If all else fails, you can try adding an auxiliary electric fan in front of the condenser, but it could impede airflow at higher speeds.
Power Steering CapacityI’m pretty sure you’ve talked about it before, but what’s a good way to increase the capacity of the power steering system for hydro-assist using the stock-style pump and reservoir? I have seen the radiator hose trick, but I thought you said it’s better to use fuel filler hose instead. Am I right about that? I don’t want to switch to a different pump and remote reservoir just yet.
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The factory power steering systems on our 4x4s were never originally designed to work with larger-diameter tires. Most of us shelve power steering upgrades until it’s too late and there is a real problem. Increasing the fluid capacity of your power steering system is a great way to help keep the fluid cool and the power steering functioning properly. The increased capacity also helps make up for the fluid displacement change caused by a single-ended ram-assist. Smaller power steering reservoirs could run dry with the ram fully extended while your 4x4 is at a precarious angle. This scenario can lead to a smoked power steering pump if left unchecked. There are several methods that can be used to increase the power steering fluid capacity. Companies such as Howe Performance Power Steering (howeperformance.com) and PSC Motorsports (pscmotorsports.com) offer aftermarket remote-reservoir kits that increase fluid capacity. Most have built-in baffles that prevent sloshing, and some have replaceable filters to ensure the fluid stays fresh. If you are simply looking for a low-buck way to increase fluid capacity on a GM P-pump with a truck-style reservoir can, then a hose extension on the top of the pump can be utilized. Avoid using radiator hose; it’s not oil resistant. It will eventually swell and weaken from contact with the power steering fluid. It’s best to use a hydraulic or fuel filler hose. These hoses are much more chemical resistant than a radiator hose and will not degrade from contact with power steering fluid. You can generally find a straight section of 1.5-inch fuel filler hose at the local auto parts store. You can then recycle a stock power steering filler neck for the lid or install a Pro-Werks (pro-werks.com) threaded bung. I’ll typically only fill the pump housing up to 1 or 2 inches below the old filler neck and use it as a baffle. This will get you about half a quart more fluid in the system and prevent leaks from sloshing.
I also like to add a 1-quart remote filter to my power steering system. This can be done with Wix (wixfilters.com) remote filter mount part number 24764, Wix filter part number 51622, and a few fittings. The filter addition nearly doubles your power steering fluid capacity and it removes contaminates from the system.
Adaptable Coolant HosesWhat’s the best way to find the correct radiator hoses that will fit with a swapped-in engine?
There are a couple of ways to find radiator hoses to fit your swapped-in engine. Some swappers try to use the universal flexible rubber radiator hoses. However, these aren’t able to make tight corners and can put a lot of stress on the radiator water inlets and outlets, which can cause them to crack and leak. The most painful solution is to mock up a model of what you need using PVC pipe and fittings, head to the local auto parts store, and then beg the counter person to allow you to sift through the wall of radiator hoses in back to try and match something up. You can generally find something that is close to what you need, but you may have to purchase, cut, and connect two or more hoses depending on the intricacy of the bends you need. I did it this way for many years until I switched to flexible stainless steel radiator tubing. Companies such as Jegs (jegs.com), Silicone Intakes (siliconeintakes.com), and Summit Racing (summitracing.com) offer universal flexible stainless steel radiator tubes in a few different lengths with rubber adapter couplings. I usually toss the rubber parts and replace them with silicon reducer couplings from Silicone Intakes. You can bend the tubing with your hands however you like, and it doesn’t put stress on the water inlets and outlets. You can also cut the tubes to whatever length you need.
No-Traction SamuraiMy Suzuki Samurai has a rear four-link suspension. It rolls on Super Swamper Bogger tires that I run at 10 psi. It doesn’t seem to have much traction in the rear. The wheelbase has been stretched out in the rear to 98 inches. I wonder about the anti-squat and how the angle of the suspension links correlates. It may be as simple as a weight transfer issue, but I do carry about 200 pounds of gear in the rear. I need more hook and I am curious if I could tune some in.
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Building a four-link with proper geometry can be a tricky endeavor. As you have noted, an improperly designed four-link can result in poor traction and handling. There are many computer programs and link suspension kits available to help get a link suspension set up right. I took a look at the suspension images you sent and there doesn’t appear to be any major geometry red flags. However, I think you may have a different issue. The good news is that it’s a really easy problem to solve. Interco (intercotire.com) Super Swamper Boggers and the other Interco bias-ply tires have large, chunky tread lugs and amazing tire carcass puncture resistance, but it comes at a cost. Your Suzuki Samurai is extremely light compared to most 4x4s on the trail; extending the wheelbase has reduced the weight loaded on the rear tires even more. I suspect that at 10 psi you are not getting much tire sidewall flex and the tread is unable to conform to the obstacles on the trail. The result would be miserable traction overall. Unfortunately, most 4x4s on bias-ply tires will need beadlock wheels to make full use of the traction potential of these tires. Given the light weight of your 4x4, I believe you’ll likely need to be in the 3-5 psi range to get proper traction performance from the Swampers. At 3-5 psi it is extremely easy to knock the tire bead off of a wheel. Give lower tire pressure a try. If it works wonders and you finally get the traction you have been looking for, consider upgrading to beadlock wheels. There are many to choose from. Also, when you do dump the air pressure down into the single digits, be sure to check the air pressure throughout the day. Higher speeds and direct sunlight can warm the air in the tires enough to increase the tire air pressure, which would lead to less traction performance. Likewise, parking overnight in cooler temperatures will decrease the tire pressure. Watch out for the common flat-spotting that bias-ply tires get. It’s especially pronounced at low tire pressures in cold weather.