Offroad Design Magnum Underdrive

The new Offroad Design Magnum Box is our super compact 4 speed transfer case system featuring our "fat shaft" technology that truly equips you to use any of the available ranges without fear of breaking the intermediate shaft.

The Magnum Box retains the 1:1 and 1.96:1 ratio that an NP205 has stock and adds an additional 2.72: and 5.33:1, all available depending on how you shift it!

If you need a NP205 for your Magnum we can build you one. Check them out here: REBUILT NP205s

As low as $1,990.00
Availability: In stock
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Offroad Design Magnum Underdrive

The Magnum Box is a planetary gear reduction box that bolts to the front of an NP205 transfer case.  This transforms the NP205 from a strong transfer case with poor low range gearing to an extremely strong transfer case with four range options giving you all the low range you could ever want. 

Bolts directly to GM/Dodge fig 8 205, GM round pattern 205 or Ford 205 with no additional adapters.

This is the heart of the system and the picture below compares it to the intermediate shaft of all other planetary gearing systems.  Our "Fat Shaft" is on the the right here, notice that it doesn't ever get smaller than the large planetary output diameter and the shaft is integrated into the input gear.  On the left is a conventional planetary intermediate shaft, notice it necks down to 32 spline.

Until now, all of the planetary underdrive systems use a 32 spline intermediate shaft (or smaller) which is the weak link in the system when using 32 spline outputs.  When that shaft breaks, you're dead in the water until you fix it!

Our giant, US made chromoly intermediate shaft is more than double the strength of a conventional 32 spline connection so it's safe to run in any gear combination.

When purchased with one of our remanufactured NP205s we will install the Magnum for FREE! NP205s can be found HERE

To illustrate how compact the Magnum 205 is here is it next to a Slip yoke eliminated NP241. Only 1.625" longer

 

Magnum Face Bolt Pattern

NP205 make

Input Gear Spline

Adapting a TH350 to the Magnum underdrive

Adapting a 700R4, 4L60E, 4L65E or 4L70E to the Magnum underdrive

Adapting a TH400 to the Magnum underdrive

Adapting a 4L80E to the Magnum underdrive

Adapting the GM SM465 to the Magnum underdrive

Adapting the NV4500 to the Magnum underdrive

Adapting most Dodge automatic transmissions to the Magnum underdrive

Adapting most Ford transmissions to the Magnum underdrive

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Magnum Box Instructions pdf 357.9 KB Download