MN Doug Nash overdrive unit for TH400

[Chris H]

I have had this one sitting on the shelf for a while, bought a Gear Vendors and no need to keep them both...

Doug Nash Engineering Dual Range Auxiliary Transmission, bolts on your TH400 transmission instead of the tailshaft housing. Gives a .75 to 1 overdrive ratio. Electrically shifted like a 2 speed truck rear end, and can stay in either direct or overdrive. Commonly used on RVs, motorhomes, bigger trucks. Probably not well suited for hot-rod gear splitting, but pretty handy for the right applications. USGear bought out Doug Nash, very similar to the Dual Range.
Your 4.10 rear becomes a 3.08 in overdrive, 4.57 to 3.42, or 5.13 to 3.85. Keep your deep gear for off the line grunt, then shift to overdrive at highway speed to lower your RPM, maybe even save some gas in the process? Or leave it in overdrive when unloaded. Or...

All manuals and electric controls are included.
$900 plus shipping (less than $75 in the US48 I would guess).