[Bradbilt]

The S42 and S47 were also available in a gas(wide ratio)
These are diesel(close ratio)

ZF5-S42----------ZF5-S47--------ZF6-S6

1st Gear:
4.14---------------5.08------------5.79
2nd Gear:
2.37---------------2.60------------3.31
3rd Gear:
1.42---------------1.53------------2.10
4th Gear:
1.00---------------1.00------------1.31
5th Gear:
0.77---------------0.77------------1.00
6thGear:
N/A----------------N/A------------0.72
Rev Gear:
3.79---------------4.66------------5.23

As far as cost, I have never spent over $450 on rebuilding a ZF5. I had over $2000 in the ZF6 in my F550. Granted it needed an input, output and main shaft. But those parts were "only" $450. The ZF6 is rated for more power(50ft/lbs) but will take MUCH more than either ZF5. With that said I will stick with my ZF5s