Ultimate Taco

Here is the final unit ready for install with a T6061-billet, five-speed manual transmission adapter on the front, a reduction box with 4.70 gears next, and an MC09 adapter plate in front of the stock transfer case.

With the new doubler kit in the truck we now had to make room for a second transfer-case shifter. It turns out that the crawler-box stick came through right where the transfer case used to be, and the transfer case happened to fall right in one of the cup holders. Other than the fact that we can now only have one drink at a time, everything worked out great. We also installed a short shift kit on the Toyota five-speed transmission. This helped give us quicker shifts through the pattern, but requires just slightly more effort.

Since the doubler moved the transfer case backwards, we also needed to modify the crossmember that supports it. Czajkowski's fabricator Andy Widner built a new crossmember that not only supports the dual-case setup, but will also allow the driveshaft to droop when the solid front axle is installed, in addition to acting as a skidplate.

Finally we headed over to Driveline Specialist to bring back our driveshafts. We had sent them there to get the rear shaft shortened and the front lengthened. Then it was time to simply bolt them back in and we were ready to go really slow.

After we had the dual cases installed, we headed to 4Wheeler's Supply in Phoenix to begin measuring for our suspension and axle install. 4Wheeler's has a long history in Phoenix, and was one of the first shops that our own editor Pw worked in when he was growing up. We wanted to come up with a flexible, but controlled, link and coilover-shock suspension for the Tacoma, and the fab shop at 4Wheeler's wasn't worried in the least that they could figure it out.

We had originally planned on a high-pinion front axle, but measuring what was under the engine revealed that a low-pinion might give us more clearance. We wanted to keep the truck as low as possible so the low-pinion would also work better in that respect by allowing the front suspension to compress more before driveshafts started hitting engine parts. We decided on a low-pinion Dana 44 measuring roughly 64 inches from wheel-mounting surface to wheel-mounting surface with the pinion offset about 9 inches from center.

Once again Dynatrac signed up as the official axle of Ultimate Adventure, so we headed down there to see how they would build our pigs this year. Another benefit of using a low-pinion Dana 44 is that the centersections are still available brand new, where there are no new castings of the high-pinion variant, and Dynatrac strives to put brand-new parts in every axle it builds. When we arrived they had machined the 3-inch tubes to step down and fit into the housing. Dynatrac presses the tubes into the centersection and plug-welds them. No butt welding here!

The first step was to press the end forgings/ tube forks/C's onto the tubes. Owner Jim McGean was out in the shop helping us, and explained how the camber is set by first pressing on the C's and then tacking them in place at the desired camber of 0 to 1/2 degree positive.

After pressing the tubes into our 44 housing, Rob Brewer checked to make sure everything was straight and true with a long bar that runs through two pucks that sit under the bearing caps. Then the many rosette plug welds were burned in to keep the tubes from ever coming out. We had the knuckle set to 4 degrees of positive caster.

We did it last year, and we liked it, so once again we are running Detroit Lockers front and rear in the Ultimate Adventure truck. We won't have the weight or rear-steer ability that we had last year, so it will be interesting to see if the performance is noticeably different. Also we repeated the gearing choice of 5.13:1, though this year we are going with a Precision Gear set as well as an installation kit from Drivetrain Direct. Detroit Locker and Drivetrain Direct are both sponsors of UA this year as well.

The ring gear is first installed on the Detroit Locker and torqued to 85 lb-ft, and then begins the process of setting up the gears until a perfect pattern is achieved. Remember that with any new gearset, careful break-in procedures help assure a long-lasting ring-and-pinion, so be sure to take it easy for the first few hundred miles and stop often to let the differential and gears cool down, and then change the gear oil after about 300 miles.

Our rear axle is the well-known Dynatrac Pro-rock 60. With tires over 36 inches, we would be pushing the limits of the stock rear axle, and the high-pinion Pro-rock should have no problems whatsoever with our lightweight Tacoma. Of course, the Pro-rock will add some weight, but hopefully in the right areas. We had the housing machined and added a differential bridge to give another option for mounting the rear suspension links. Next month we'll show you how these axles will fit under our Ultimate Taco.