By Christian Sturtz, [email protected]
Photos by Christian Sturtz
The more gear options, the better! Advance Adapters’ 4-speed transfer cases allow you just that – more options. All 4-speeds come with a 2.72 reduction on the planetary assembly. It is up to you to choose the ratio on the main Atlas. Available ratios are 1.5, 2.0, 3.0, 3.8, and 4.3. These give you a final low range out of the transfer case from 4.08:1 to 11.7:1; the choice is up to you, your vehicle, and your driving style. We ordered our Atlas with a 1310 CV yoke but decided to go with a 1350 CV yoke, so all u-joints are the same size. (Figure 1)
In our Jeep LJ project, we chose to go with one of the largest spreads we could get, which is the 4.3:1 in the main Atlas. Not thinking we would use the 2.72:1 and the 4.3:1 together, but that we would have two different ratios available for different types of terrain. We would also have the 11.7:1 available if we ever needed it.
In most applications, Atlas transfer cases are straightforward to install. We will highlight the installation of a 4-speed Atlas in an ’05 Jeep LJ. This install would be very similar in most other applications. We started by supporting the transmission and removing the cross member/skid plate. The transmission mount can be removed along with the vent hose and both electrical connectors. The drive shaft and shifter linkage can be disconnected and removed. Finally, the transfer case can be unbolted from the transmission and removed. (Figure 2)
Most of the time, the Atlas will have to be test-fit a few times to get optimal fitment. When you do this, install it with just two studs to save time. The front mounting surface of the transfer case allows you to clock it in several different locations. After we figured out where we wanted it, we lowered it and installed the rest of the studs. Then we filled it with oil, installed the planetary shifter, and part of the linkage for the main case. (Figure 3)
The transfer case was finally bolted in. The speedo assembly was removed from the old transfer case. Wires for the 4×4 light and speedometer were lengthened. Next, the transmission mount was installed. Then the planetary shifter mount was installed through the floor. (*Tip: on LJ applications there are only two places it fits well, on one side or the other of the emergency brake lever) It has to be nearly perfect; take your time. (Figure 4)
When you do the main case shifters you want the transfer case at the correct installed height (ride height). This can dramatically affect the shifter’s location. We used washers and stacked them to figure out the length to cut the tube on the shifter mount. (*Tip: take your time, this is difficult, but if done correctly, it will come through the original shifter hole and look amazing) The shifter boot works best at about a 45-degree angle. This requires you to make two small filler plates to patch the original shifter hole. After figuring out the length of the two shifter linkage rods, heat shrink is installed to keep them from unscrewing. Make sure the shifters will go into all positions without hitting each other or the floor/console. The boot gets installed upside-down on the main shifters and in regular orientation on the planetary box. (Figure 5) The console can now be re-installed. We put a couple of cable clamps to hold the shifter linkage cable. Then we installed the new Tom Woods driveshafts and the crossmember/skid plate. Atlast! (Figure 6)
Parts Used:
Advance Adapters
4-Speed Atlas with 4.3 Ratio and 1350 CV Yokes
Sources:
Advance Adapters
4320 Aerotech Center Way
Paso Robles, CA 93446
1-800-350-2223
Tom Woods
2147 Rulon White Blvd (Ste 103)
Ogden, UT 84404
1-801-737-0757
GEARWRENCH
APEX Tool Group
910 Ridgebrook Rd. (Suite 200)
Sparks, MD 21152
1-800-688-8949
Eastwood
1-800-343-9353
