As mentioned in PART 1 and PART 2 of the 2022 Ultimate Adventure Ultimate Shop truck build, we are starting with a 2006 2WD V-8 Tundra Crew Cab that was T-boned in the bed of the truck. That did lots of frame damage, mostly behind the cab of the truck, which is basically perfect. We did spend some time with a port-a-power straightening the rear frame rails of the truck before we got it inspected, and got a restored salvage title for it, but at the end of the day we realized we would probably be better off scrapping the rear frame rails to build our own out of fresh steel from Industrial Metal Supply (IMS) in Phoenix, Arizona. So, as with most any good project, the mess had to get bigger before it got smaller. We had to start cutting and designing a new rear frame. Our plan was to build a rear frame that would be straight, square, and quite a bit stronger than the wavy factory frame was. We also wanted to shorten the truck as much as possible without making it look strange or too short. Here is how we began the rear chop of the truck and what we did to bring it back up to standards, giving us a good place to start building a useful and trail-friendly bed.

The plan for the truck involves some heavy-duty drivetrain, a rollcage, and a utilitarian bed with some added structure tied to the 'cage and a slight shortening to lose some wheelbase and gain some much-needed departure angle. The factory framerails behind the cab were a wavy mess, so out came the measuring tape and the reciprocating saw so we could chop off the damaged rear of the factory frame. We decided to make our cut behind the cab, just aft of a factory plate gusset inside the frame. We needed to remove the fuel tank to make the cut and to push the rear axle forward. We would have liked to have a wheelbase of about 130 inches, but we settled on 136 inches after taking into consideration the need to push the front axle forward and keep the rear tires far enough away from the back of the cab that the truck didn't look strange.

Truth be told, chopping the rear of a truck's frame off would make a great time to convert the rear suspension to a link setup, but we like leaf springs, especially in the back of a truck. Also, we want this truck to be retro, a nod to 1980's Toyota trucks. For those reasons we are gonna stay with leaf springs. We will be using springs from Skyjacker and for that, the easiest route is to go with some K-series 4-inch-lift rear springs. We will reuse the spring hangers and the tension shackle brackets from the Tundra frame, and the springs will eventually hold a GM full-float 14-bolt corporate rear axle from a 1999 Chevy Van. The van axle is the widest 14-bolt we can get from a junkyard, and 14-bolts are near indestructible for a junkyard-available axle.

We chopped the frame and built two new rear framerails out of 2-by-4-inch, 0.120"-wall rectangular steel tubing from IMS. These tubes sleeve inside the stubs of the factory frame and weld in place, and are tied together with another length of 2x4 rectangular tube. We will also make gussets out of ⅛-inch steel plate to bridge the angled cope that is butt-welded for the rear frame. We remounted the spring hangers and shackle brackets but after deciding that the shackle brackets were too high and the front spring hangers were too low we repositioned them, raising the spring hangers and lowering the shackle brackets to help keep the springs relatively level. We then used Anti-Wrap Leaf Spring Perch Pair for GM 14 Bolt from Barnes 4WD and their recommended 3.5-inch ID U-bolts and spring plates. These parts are beautiful and Barnes has helpful and knowledgeable staff, a great website for searching for parts and a huge amount of suspension parts for fabrication.