Vehicle: 2003 Chevy HD Crew Cab
Engine: Duramax Diesel
Transmission: Allison 6 speed auto
T-Case: New Process 263 electric shift
Axles: American 11.5 rear, 1990 Ford high pinion 60 front
Tires: 44" Super Swampers Trxus on 16.5x12 wheels
Suspension: Rear lift springs along with 6" blocks, 4" front Superduty springs with WFO brackets
Matt bought his HD Chevy brand new in 2003. His intent was to purchase a truck that was going to last a long time as an every day work truck. From the beginning, Matt wasn't afraid to get his truck dirty. After a few months, he was ready to lift it. He called down to the guys at Whiplash Suspension. They installed their 18" extreme lift kit. The truck drove great on the highway, but seemed to be a little weak when it came to off-road. Just about every time Matt took the truck off-road, something broke. If it wasn't the front driveline, it was the tie-rod ends or idler arm assembly. The last time the driveline broke, it actually took out the electronic shifter on the transmission. This was the last straw that broke the camel's back. Matt decided to put a straight axle in it.
Matt wanted to do the job himself, so he bought a bracket kit online. The kit came with new leaf spring brackets and 4" Ford Superduty leaf springs. To go with the kit, Matt found a 1990 Ford Dana 60 front axle. After spending a few weeks taking out the IFS and working on the truck, he decided he didn't have the time to finish the job. He called up WFO and dropped off a "work in progress" for us to finish. After the tow truck dropped it off, we rolled it in the shop.
The first thing we noticed when the truck was dropped off, was that the leaf springs brackets that he had bought were too wide. They were for a 97 and newer ford axle, with a spring width of 38". We needed around 36" for the 1990 axle. We decided to make our own brackets. Beau got on the computer and started drawing.
While Beau was designing the brackets, Phil started to clean up the frame rails. After cutting off the existing IFS brackets with the plasma cutter, he cut out both cross members. Neither of them looked like they belonged. We no longer needed them to hold the A-arms on. A new cross-member, built from 1.5" tubing, was welded in the front. The rear one was simply left out.
The next order of business was the frame rail. After cleaning off the IFS brackets with the plasma cutter, there were still two large factory holes in the frame. We thought about it for a while, and decided to plate over the entire frame rail with " steel. Phil made a cardboard template, and then cut the plate out of steel. After welding in the plate, the frame looked much cleaner.
Meanwhile, Beau was done drawing the new leaf spring hangers. He headed up and had the brackets cut out of plate steel with the waterjet. After the brackets were cut out, they were broke, and then welded together.
With the new brackets bolted back in, the leaf springs and axle were also bolted back under the truck. At this stage, a WFO modified Superlift 1104 pitman arm was bolted on the stock steering box. The WFO crossover steering was also put on. With the steering in place, it was easy to measure for the dimensions of our track bar. Once again, Beau headed back to the computer to design the track bar brackets.
While Beau was working on the track bar brackets, Phil bent up some shock hoops to fit our Dual Bilstein shocks. While Phil was dialing in the shock mounts and hoops, we noticed that we weren't going to be able to fit a front driveline in. The angle was going to be too steep. We decide that the only way to fix this, was to rotate the pinion on the axle. In order to do this, the entire axle needed to be stripped down, and the outer C's cut off. The C's could then be rotated and pressed back on. Our goal was to get the pinion pointing straight at the transfer case.
Once we figured out how much we needed to turn it, the axle was taken out, torn down, and rotated. At the same time, the kingpins were rebuilt, and the wheel bearings packed with new grease. All extra brackets were also cut off the axle. The axle was cleaned up and painted before it was re-installed.
When we bolted the axle back in, we decided to use regular u-bolts, and new leaf spring plates. The housing was notched a little on the pumpkin side, and the axle was bolted back in, using WFO spring plates. After that, the new track bar brackets were welded on, and the track bar bolted in. We were very careful to make the track bar the same length as the draglink, as well as the same angle. This will eliminate all bump steer, as well as any wander on the highway. The adjustable track bar was built with a " heim joint on the axle end, and a poly bushing on the frame end.
The shocks and brake lines were bolted on, and the truck was ready to take for a test drive. After a few alignment adjustments, and the addition of a steering stabilizer, the truck drove great!
The last thing to deal with was the transfer case. The stock transfer case did not have a fixed yoke. The driveshaft actually slipped in and out of the t-case. This style of driveline is not what we want for the Straight axle swap. Pro-Comp offers a slip yoke eliminator kit for this case. Rather than use the Pro-Comp kit, we decided to make a collar that holds the slip yoke in a fixed position. We aren't sure if it is going to work, but it only took an hour or so to make. Not to mention, it simply bolts on. We will let you know how it works. Matt took his truck back without a front driveline, due to the fact that we are waiting to put lower gears in it. Once we do the gears and driveline, we will update you and let you know how it all works.
Update: We finally ordered a front driveshaft from Tom Woods Custom Driveshafts. The shaft was built with a standard 1310 CV joint, just like stock. However, when Tom built the shaft, he clearanced the CV for more angle. He also installed a spicer 6" slip yoke at the axle end of the shaft. Due to fact that the axle was rotated up, there were no problems with the CV binding up. We will just have to see if the WFO custom slip yoke eliminator will work out!