Ultimate Avalanche - Part 2

The final adapter setup we used included an adapter on the back of the automatic and a 1 1/4-inch spacer. We clocked the Atlas to get a near flat belly under the truck, and only had to notch the crossmember slightly. A tranny mount from Energy Suspension fit perfectly on the adapter, but we had to slightly modify the crossmember. High Angle Driveline outfitted our gearbox with a rear-driveshaft parking brake since none of our axles had parameters for one. We like to be difficult, thus we ended up modifying his mounting bracket so we could reach the stock e-brake cable, but it locks up great and should hold the truck on any hill if need be.

To shift the transfer case we cut a hole in the tunnel right beside the driver's right leg. A little heat from the torch allowed us to bend the levers slightly, and we were quickly shifting with ease. The fit was so easy we almost thought GM might have once been considering an Atlas as a standard feature. Yes, we'll keep dreaming.

With the axles in place, we moved to the driveshafts. Again we contacted High Angle and quickly had two shafts at our door. The rear shaft has a 1410 joint at the axle and the 1-ton 1350 CV at the Atlas, and installed like a dream. The front shaft was supposed to have a 1410 CV to deal with the steep angles and another 1410 joint at the axle. When lack of sleep and lack of lunch are combined with not enough space for the awesome 1410 CV, frustration kicked in. The problem was that the CV was just too big and burly and was not going to clear the automatic transmission. We finally settled down and decided on a special smaller U-joint, that High Angle wanted us to test, which would handle the angle. We have every confidence that it will hold up, but even so we packed a spare.

The final mission for this month was to get a signal from the transfer case to the computer, to convince everything to work in harmony. Since the stock transfer case had a speed sensor, we needed something that would duplicate the signal to the computer, but it had to be run off the Atlas. The still-unsolved solution came from Abbott Enterprises in the form of a Signal Generator and an Electronic Ratio Adapter (ERA).

The Signal Generator plugs into the speedometer gear on the Atlas, and then produces an electrical signal. This signal, which runs through the ERA to the computer, originates from the generator mounted under the driver's seat by Eric Garding of ORU. Theoretically, after some test runs you dial in the perfect setting in the ERA and the speedometer works. This let the truck run and drive and had the tranny shifting. However, there were still some "check engine" lights on, and we felt there were some issues with the way the tranny was shifting. We'll explore those issues and others next month.