Vehicle: 2002 Dodge extended cab, 1/2 ton
Engine: Cummins Turbo Diesel
Axles: Dana 70 HD rear, 89 Ford High pinion 60 front
Tires: 39.5 Super Swamper Trxus
Suspension: Leaf spring rear, FOX 2” remote reservoir, nitrogen charged, Coil-overs in front
The Project: (Click the icon for photos)
I picked up the phone, and Brent proceeded to explain to me the problem he was having with his 2002 Dodge. After driving the long bed, extended cab, 3/4 ton diesel for year, he had decided to lift it. Not many people had big Dodges, so Brent decided to be different. He quickly realized why there are not many big Dodges. It is because nobody really makes a lift kit that is over 6”. He finally found a 10” long-arm kit from Whiplash. With the help of some friends, the lift kit was installed, along with 4 39.5 Super Swamper Trxus tires. The truck looked great, but there were some small issues.
After numerous driveline problems, and major handling problems, somebody mentioned to Brent that he should give WFO a call. I happened to be down in his area for a wedding, so I stopped by to check his truck out. I quickly noticed a few things that I didn’t like. The main problem was the driveline. Dodge trucks do not have locking hubs, so the driveline spins at all times.
With the driveline at such an extremely steep angle, not only does is wear out fast, but it also has a tendency to bind up. Brent had already clearanced his CV to handle the steep angle, however, the driveline would still bind when the suspension drooped out. The only other thing he could do was turn the differential up. When Brent did this, it allowed his driveline to spin, but it brought the caster angle to a positive 5 degrees. An acceptable caster angle can range anywhere from 3 to 7 degrees of negative caster.
The more caster you add, the more the car wants to drive in a straight line. To give you an idea, a dragster runs about 18 degrees of negative caster. On a dragster, if you turned the tires, and let go of the wheel, the weight of the front end would pull the steering wheel right back to the center.
With the caster angle off so much, the truck would wander quite a bit. In fact, it did not want to drive straight. It would catch the grooves in the freeway, and try to jump from lane to lane. Some of this wandering was also due to the fact that the tires were non-radial. A biased ply tire will have much more of a tendancy to grab grooves in the road. This is due to the fact that the contact surface on the road is much smaller.
Non-radial tires tend to drive on the center of the tread. The radial tires have much more structure inside, which allows the tire to keep its shape. The biased ply tire will actually balloon up as the vehicle gains speed. When the two tires are compared, side to side, it is easy to tell the difference. The radial tire looks more “square”, and tends to contact the road with the full width of the tire.
There was one last issue to deal with. Brent’s truck was so high, that the steering linkage itself needed a little attention.
The general rule of thumb is that anything with more that 6” of lift should really have crossover steering. Crossover steering is where the draglink actually steers to the top of the knuckle, instead of the middle. This keeps the steering and suspension geometry closer to the stock angles, allowing every aspect of the suspension and steering to function like it was designed from the factory. In Brent’s case, adapting crossover steering to his factory Dana 60 front is very expensive and time consuming. It would require the use of a completely new knuckle. In fact, I don’t even know if anyone makes one for his application. It was this last problem that made me decide to swap in a Ford, Dana 60 front axle.
When Brent dropped his truck off at WFO, we had 4 different issues to deal with: Driveline angle, Caster angle, steering geometry, and locking hubs. It seems the answer to our question would involve swapping in an older Ford front axle that could be easily tweaked to attack our problems.
The Dana 60 that comes in newer Dodge trucks is actually an inferior axle. From the outside, the large housing and 4” tubes are just as they look, plenty strong! However the insides are a little weak. For some reason, since the late 90’s, Dodge has been using 30 or 32 spline axle shafts on all 3/4 and 1 ton front axle assemblies. The axle shaft u-joints are still a full 1 ton size, but the shafts are the same diameter as most 1/2 ton vehicles. Another downfall is the fact that they use a unit bearing outer. The unit bearing is a very strong and maintenance free sealed wheel bearing in a stock application. However, it does not allow for any needed maintenance that comes along with larger tires. The unit bearing cannot be adjusted, or re-packed with grease. Due to the fact that it is designed for a factory sized tire, it tends to wear out faster with a larger tire. Unit bearings can be very expensive to replace! It is not out of the ball park to spend $1000 just for parts to replace the unit bearings.
Another downfall that comes with the Dodge unit bearing front axle, is the fact that it does not allow for locking hubs. This means that even with the transfer case in neutral, the front driveline, axles, and differential, are all constantly spinning. Not only does this wear out all of your drive-train components faster, but it also hurts your gas mileage. This is where the older Ford 1 ton front axle comes in. We chose to use a front axle from an 89 Ford F-350. Not only is it drivers side pumpkin (like the dodge), but it is high pinion for better driveline angle. It has locking hubs, large greasable wheel bearings, and a steering knuckle that will accept crossover steering. It was the perfect axle to start our project with.
The first thing we did was re-build the axle. It was completely stripped down to the bare housing. All un-necessary brackets and hangers were plasma cut off, and ground clean. After being hot tanked, the gears and bearings were put back in. The kingpin outers were then completely rebuilt. The rotors were turned, and all new wheel bearings and seals were installed. The calipers were traded in for a loaded set of rebuilt calipers. After the differential cover was sealed up, we were ready for Brent’s truck.
When Brent dropped the truck off, we put it on the lift and removed the stock Dana 60 front axle. At the same time, we removed the Whiplash lift coils and 6” coil spacers. With the axle out, we rolled the new axle under, and started thinking. The first thing we realized was that we didn’t want to re-use the Whiplash coils and Monster Spacers. We decided we would build the front to accept coil-over shocks, and keep the whiplash links. A set of 12”, dual rate 2” FOX coil-over shocks were ordered.
We did decide to modify and use the existing Whiplash links and brackets. The links had rubber bushings at each end, and were not adjustable. Instead, they had slots in the brackets, and adjustable cams. This style of adjustment tends to work loose. We wanted something a little stronger, so we decided to make the frame end of the links fixed, and the lower end accept adjustable heims.
The Whiplash upper link brackets were then un-bolted from the frame. We chopped off the bottom 3” that housed the old cam slots. New bolt holes were drilled higher up on the bracket. After a fresh coat of paint, the mounts were bolted back on. It was time to modify the links. The existing rubber bushing at the frame end of the link was re-used. At the lower end, the bushing was cut off. Due to the fact that the tubing was a weird size, we had to make 4 tube inserts to hold our 1 1/4 FK heims. After a couple hours on the lathe, the inserts were made and welded into the links.
We changed our focus to the brackets on the axle.
Once we decided we were going to use heims at the axle end, we made our 4 link brackets from cardboard, and transferred them into the computer. At the same time, we drew the new track bar bracket for the axle, as well as the lower shock mount brackets.
With those brackets drawn up, it was time to figure out what to do with the upper coil buckets. After we all stared at it like idiots for a while, Beau came up with a bracket that bolted into the dodge bucket. After it was designed in cardboard, he transferred it to CAD on the computer. With the last bracket designed, Beau headed up to get everything cut on the water jet. All mounts were cut from 1/4” plate steel, including all bolt holes.
Once Beau was back with the brackets, it was just a matter of welding them on. The Link brackets were welded on solid, while the other brackets were tacked together. This would allow us to bolt the axle in, and check our angles and dimensions before everything was set in stone.
Before we cycled the axle and checked our angles, we noticed that the existing Whiplash drop pitman arm had WAY to much drop. It was putting too much stress on the steering box, and had already come loose once. We replaced that pitman arm with a standard 4” drop arm.
At the same time, the pitman arm was reamed out to accept a large Chevy, double pivot draglink end. This keeps the steering linkage from binding at full droop. A new track bar was built, using QA-1 3/4 heim joints, and 1.5x.219 wall DOM tubing. Weld in inserts were used at both ends. A new draglink was also built to attach the WFO crossover steering arm to the new pitman arm.
The draglink was built from 1.25”x.219 wall DOM. This tubing was drilled and tapped to accept the Chevy, double pivot draglink ends. At the same time, the knuckles were reamed out from the top side to accept Chevy tie-rod ends. A custom HD tie-rod was built with weld in inserts from 1.5x.219 wall DOM. At this point, the suspension was finally cycled from full droop to full compression. We made some small adjustments to the track bar bracket, in order to clear the coil springs.
The links were adjusted until the tire was in the best place for maximum clearance of the fender. We also checked to make sure the steering and track bar had a free range of motion.
With all other components working correctly, we finally attacked the sway bar. We found that our best bet was to bolt the sway bar in the original position. From there, we custom bent some drop down links, in order to clear the draglink and tie-rod. New link mounts were then welded to the axle tube. New rubber bushings were used on the ends of the new sway-bar links.
The next order of business was the brake lines and the driveline. New stainless brake lines were built to take the place of the factory rubber lines. The original driveline was bolted in, and checked for clearance. It was a hair short, due to the fact that the front axle was moved around 3” forward. Luckily, with a link setup, the driveline does not need much movement in and out. The CV had already been clearanced for maximum angle. Rather than buy a $600 high angle driveline right then, we decided to make due with Brent’s driveline. The front suspension was drooped out, while spinning the driveline at the same time.
The driveline should spin freely throughout the entire suspension cycle. If it doesn’t, the driveline will break the first time you go up a hill in 4 wheel drive. Unfortunately, without the expensive high angle CV, Brent’s driveline started to bind just before full droop. We built a limit strap to keep the suspension from coming out any further. This will still allow the suspension to have full articulation from side to side. If you are building a rock crawler, it will actually help you get better traction while climbing hills.
With everything finished up, the front end was completely torn out again. All parts were finish welded, cleaned, and painted. On the final install, a steering stabilizer was added between the draglink and track bar. Another one was added down low on the tie-rod. With such large non radial tires, this should help keep the tires from developing a high speed wobble.
The shocks were charged with nitrogen, and the truck was taken on its first test drive. Everything seemed to work out great. Without the driveline spinning at all times, it felt like it drove much smoother than before. It could also be driven with 1 finger, instead of 2 hands! It still had a small wander when it hit grooves in the road. We concluded that the last little wander was due to the non-radial tires.
In the end, Brent was much happier with his truck. Not only did it drive much better, but it was also much stronger and safer. All of the components in the front were now heavy duty, including the new 35 spline Ford Dana 60. The locking hubs in the front will also save him in gas mileage. At the same time, the softer ride, and nice look of the FOX coil-over shocks makes the truck a real eye catcher.