Atlas Transfer Case Early Ford Bronco Install Page 1, by Advance Adapters Inc.

Early Bronco Information

Installation

The Bronco Dana 20 transfer case has a stock rotation of 42 degrees. When installing the Atlas, we offer both this stock rotation and a 7 and 14 degree higher rotation for clearance. On the vehicle we installed the Atlas transfer case into, we opted to use the 7 degree higher rotation which provided extra front driveshaft clearance on the exhaust and crossmember. This rotation also allowed us a cleaner shifter installation. The only area of concern was the frame rail clearance, which we felt was still adequate. (On some applications, your brake lines may need to be moved to provide the extra clearance between the Atlas and your frame rail).

The project that we completed was on a 1977 Bronco with a late model injected 302, and a C4 automatic transmission. The information contained in this section was obtained while completing this installation. The biggest difference on this vehicle compared to other Broncos (with reference to the transfer case installation) would be the transmission that was either stock or retrofitted. The Atlas should fit properly on all other applications; however, the shifter linkage or floorboard may need to be modified to obtain proper shifting clearance. Your Bronco should be equipped with a minimum 2" body lift. This will aid in shifter clearance.

The stock Bronco Dana 20 transfer case is normally indexed onto the stock adapter housing with an aluminum bearing retainer. When using the Atlas, this aluminum retainer will be removed because the Atlas has its own indexing plate. We have found on some stock adapter housings that Ford used a one piece adapter housing with a cast-in retainer. On these applications, your stock tailhousing adapter will need to be machined. If you find this to be the case, please contact us for the necessary machining specifications or for a replacement housing. When removing the stock transfer case and exposing the tailhousing adapter, you'll also find that Ford used a large dowel pin located at the top of the stock housing (shown above left). This dowel pin must be removed (shown above right).

With the two different stock transmission/transfer case combinations, spline engagement is always a concern. The Atlas was designed to obtain the utmost spline engagement. Ford used two different transfer case input shaft lengths. Since this problem exists, we have opted to design two different length input shafts for the Atlas to match the stock. The long input was normally found on the T&C transmissions and the shorter input on the C4 transmissions. When ordering your transfer case, this should be considered. If a long input gets ordered and you needed the shorter style input, the long Atlas input shaft can be shortened .300 inches.

The speedometer housing on the Atlas transfer case is a stock 1982-86 Jeep application. To hook your speedometer cable onto the Atlas, Nevada Speedometer offers the necessary components to couple your stock cable to the Atlas. If your vehicle's engine requires a pulse generator, they can also assist you in this area. Their phone number is (775)358-7422.

The stock Bronco Dana 20 front driveshaft uses a C.V. yoke on the transfer case. This transfer case also had a breather located right on the transfer case. The Atlas has a brass 90 degree elbow on the top of the transfer case for a breather tube to be installed. We recommend that you obtain a 3/8" fuel hose and run it from the transfer case to the back side of the firewall. The end of the tubing that fastens to your firewall should also be equipped with a breather vent. This provides two benefits. First, the vent will eliminate transfer case pressure. Second, the breather located on the backside of the firewall prevents water from entering into the transfer case.