Right out of the box it had a gear ratio of 13:1 and a speed of 85 SMPH. This is much too fast for transfer service. With a supply of NWSL tower gears on hand, some measuring and head scratching , a new gear train, of 30:1 and speed of 35, was developed. The tower gears are mounted on shafts and all except the motor spline input and truck shaft output are IDLERS which do not effect ratio. The problem was, how to double gear reduce using the towers and possibly change the tower to truck shaft ratio.
Truck shaft worms and axle gears were replaced with a NWSL set adding power to the center drivers, changing the ratio from 13 to 15.
The original tower gears were all 19 tooth and sloppily meshed. It was impractical to change the truck shaft gear. With a closer mesh, a 14 tooth input gear would drive a 26 tooth for a ratio of 1.4444. The step gear ratio was 26 to 19 or 1.3684 for a total of 1.9766 or close to 2:1. This gave a final ratio of close to 30:1 and a speed of about 35 SMPH.
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TOWER MODIFICATION
Just visible above housing next to tower is the truck shaft gear. To the right of it is the housing cutout to clear large 26 tooth gear. Note lube spattered on housing while testing.
The input gear shaft was lengthened and a spacer added between it and the tower to mate with the added stepgear. This required adjusting the spline shafts accordingly. The step gear shaft was also lengthened to accommodate the additional gear. Short lengths of tubing were crimped on the opposite tower side of the shafts to secure them.
The top of the truck housing under the 26 tooth gear had to be cut away to clear it.
