underdrive auxillary trans

teamjnz · December 18, 2005

I've been entertaining the thought of gettin an underdrive auxillary transmission for more power when towing heavy loads and fun factor when not towing. They are expensive and then the installation costs.

Anyone have one or have used one?

teamjnz

vhato · December 20, 2005

I've been entertaining the thought of gettin an underdrive auxillary transmission for more power when towing heavy loads and fun factor when not towing. They are expensive and then the installation costs.

Anyone have one or have used one?

teamjnz

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A user named James B. on FullSizeChevy.com installed the gear vendors OverDrive Unit. This unit gave him a gear between every shift as well as a double Overdrive. It did nothing for dead stop 1st gear pulls, but once it shifted from 1st to 1st and a half, hauling a$$ was redefined. He installed it himself and only needed a new driveshaft to make up for the added length of the T-case.

chris_kucia · December 21, 2005

On a 4x4, it would seem to be pretty complicated.

If one of the two ratios is 1:1, then you could install the overdrive aft of the transfer case, but you would have to be absolutely certain that you never had it in the other ratio while engaged in 4wd or one of the differentials will probably end up in pieces.

The other alternative would be to put the unit between the trans and transfer case.

That would required new front and rear driveshafts as well as possibly modifying the cab floor to fit the transaxle hump. May also require modifying/relocating the trans crossmember.

asilverblazer · December 21, 2005

Klune-V has a unit that would work. It mounts between the transmission and transfer case. For the most part it was a bolt on deal, except for moving the cross member back, and drilling a hole for the cable shifter. I wanted one, but the cost seemed a bit too steep for me, besides I wouldn't have used it very often. Longer/shorter driveshafts were required and some little adapter thing that they sell to mate up the input/output shafts... Overall length was 9" maybe?