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). ATLAS FRONT D.S. CLEARANCE STOCK DANA 20 FRONT DRIVELINE
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 (regarding 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. BRONCO C4 TAILHOUSING DOWEL REMOVED
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 the transfer case.
The twin stick configuration for the Bronco applications PN303004L was designed around the C4 transmission configuration. There are numerous transmission options available for the Bronco's; therefore, this shifter configuration may not work in all vehicles. You may be required to modify the shift handles to work in your vehicle.
Shifter linkage upgrades: The connection rods for the Atlas were designed to be universal so they could be adjusted for the various drivetrain lengths. The stock linkage works well for the majority of applications and vehicles. The extreme racers and rock crawlers on the other hand were looking for a linkage that would withstand the abuse that they are putting their rigs through. The two kits offered are upgrades that work with the standard handles and use heim joints that are bolted to the Atlas linkage. Anyone can upgrade to this kit as it will work on all Atlas ridged mounted twin stick applications. PN303040 or PN303041.
Use the recommended 2 quarts (2-speed Atlas) or 2.5 quarts (4-speed Atlas) of oil. If the unit is overfilled, it will cause the unit to vent oil out the breather hose.
Stock location STOCK SHIFTER LOCATION
Custom Location SHIFTER IN CUSTOM LOCATION
The stock Dana 20 transfer case measured 10-1/4" from the surface of the stock adapter housing to the face of the output yoke. DANA 20 LENGTH