• JP Magazine
  • Dirt Sports + Off-Road
  • 4-Wheel & Off-Road
  • Four Wheeler

Dana 300 Transfer Case - D3: The Second Coming

Posted in How To on July 1, 2008 Comment (0)
Share this
Dana 300 Transfer Case - D3: The Second Coming
The STaK 4x4 Dana 300 Replace-A-Case is a heavy-duty option for those wanting to improve the durability of their stock Dana 300 transfer case or even to replace a chaindriven T-case with the more proven geardriven design. The STaK 4x4 Dana 300 Replace-A-Case is a heavy-duty option for those wanting to improve the durability of their stock Dana 300 transfer case or even to replace a chaindriven T-case with the more proven geardriven design.
The Replace-A-Case is offered as a bare case or as a complete built unit. Shown here are a variety of the components used to assemble the Replace-A-Case, including all-new stainless steel hardware for joining the case halves, billet aluminum input-shaft support and inspection cover, a universal- shifter assembly, new shift rods, new shift forks, and new seals. The Replace-A-Case is offered as a bare case or as a complete built unit. Shown here are a variety of the components used to assemble the Replace-A-Case, including all-new stainless steel hardware for joining the case halves, billet aluminum input-shaft support and inspection cover, a universal- shifter assembly, new shift rods, new shift forks, and new seals.
The Replace-A-Case is manufactured from cast 356 alloy aluminum that is then hardened to a T6 condition for ultimate strength. The profiles of the case halves are fully CNC-machined for a secure fitment. The Replace-A-Case is manufactured from cast 356 alloy aluminum that is then hardened to a T6 condition for ultimate strength. The profiles of the case halves are fully CNC-machined for a secure fitment.

STaK 4x4's Dana 300 Replace-A-Case has put the Dana 300 transfer case in the same class as GM's 350 small-block V8, where used donor parts such the 350's block or the 300's housing are no longer required for assembly. With a diminishing amount of usable Dana 300 donor housings available in wrecking yards these days (the Dana 300 hasn't been used in a production vehicle since 1986), the Dana 300 Replace-A-Case effectively extends the life of this stout geardriven transfer case that has dutifully served in multiple makes of 4x4s during its multiple-year span of production.

The Dana 300 Replace-A-Case consists of two case halves that are manufactured from cast 356 alloy aluminum and then hardened to a T6 condition. Each case half offers thick walls to hold up against case deflection under hard acceleration. In order to maintain tight tolerances throughout the assembly, the profiles of the case halves and all bearing locations are fully CNC-machined to exacting specifications. The case halves are joined using 3/8-16 stainless steel socket-head cap screws to ensure positive attachment and further increase the unit's strength.

In addition to bringing more overall strength to the Dana 300, the STaK 4x4 Replace-A-Case is impressively versatile. Its design allows it to be used as a direct replacement for less desirable chaindriven transfer cases such as the NP231 in Jeep YJs and TJs. This is achieved without using the common method of mounting the Dana 300 upside down to turn it into a driver-side drop transfer case. Several clocking positions are already in place on the Replace-A-Case to suit the mounting needs of many applications, and many different input splines are also available. When used to replace an NP231 transfer case in Jeep TJs and YJs, the Dana 300 adds approximately 9-1/2 inches to rear-driveshaft length, which will effectively decrease the operating angle of the rear driveshaft in these short-wheelbase rigs. The Replace-A-Case accommodates the factory TJ and YJ speedometer-sending units, and STaK offers a TJ-style shifter that's designed to fit through the factory hole in the transmission tunnel as well. A universal shifter is available to suit other applications and can be modified as needed to meet most needs. STaK can also provide adapters to mate the Dana 300 to most GM, Ford, and Jeep applications.

View Slideshow
The size of the Replace-A-Case isn't that much larger than the stock Dana 300 case. The shifter configuration is centered on the STaK 4x4 unit compared to the offset of the stock case. The size of the Replace-A-Case isn't that much larger than the stock Dana 300 case. The shifter configuration is centered on the STaK 4x4 unit compared to the offset of the stock case.

As far as building a Dana 300 without a Dana 300? It can be done using the Replace-A-Case and all new heavy-duty aftermarket components like a 32-spline front-output shaft or a 32-spline rear-output shaft that uses a shorter tailhousing manufactured from billet aluminum (STaK offers these too). Also readily available for the Dana 300 are 4:1 Low gearsets as well as bearing rebuild kits. Of course, this isn't your only option. You can also assemble a Dana 300 using the Replace-A-Case and quality used components from an '81-'86 Dana 300 core. This will create a stout transfer-case assembly that can be upgraded over time as needs and funds dictate. Either way you slice it, new parts or old, the STaK 4x4 Replace-A-Case is an awesome upgrade to any Dana 300 transfer case and a great option for those eager to step up to a geardriven transfer case without the cost of purpose-built Low-geared units.

The split case design of the Replace-A-Case eliminates a need for the bottom inspection cover and also makes the installation of larger 4:1 gearsets much easier. The split case design of the Replace-A-Case eliminates a need for the bottom inspection cover and also makes the installation of larger 4:1 gearsets much easier.

DANA 300 OVERVIEW
The Dana 300 transfer case uses all helically cut gears and a cast-iron case. It benefits from a compact size and its versatility in being able to mate up to a variety of transmissions. Available in '80-'86 Jeep CJ-5s and CJ-7s, two versions of the Dana 300 were produced: a reputedly stronger short version and a long version. The reasoning for the two versions is said to be due to the varying wheelbases of the CJ-5 and CJ-7, with the weak link in the long version found along the mainshaft. Both offer a 2.62:1 Low-gear ratio and use an aluminum tailhousing, a 1-1/4-inch intermediate shaft, and 23-spline input shaft. There's also a Scout Dana 300 that was used in the '80 International Scout II. A few differences exist between the Jeep and Scout models, but most importantly, they do not share the same bolt pattern. The Jeep 300 uses a round six-bolt pattern. The Scout 300 uses a four-bolt "Texas" pattern that is essentially the same pattern as the five-bolt Dana 20, making it an excellent swap candidate for early-CJ owners seeking a lower gear ratio.

View Slideshow

Sources

Stak 4x4
El Paso, TX 79936
915-584-2400
http://www.stak4x4.com

Related Articles

Comments

Connect With Us

Newsletter Sign Up

Subscribe to the Magazine

Sponsored Content