Yeah, 5 different combinations of trannies/gearsets seems like a bit of overkill. I got lucky with the one I bought - it is the S47 (stronger of the 2 trannies) with the 5.08 first gear.

Of the three S47 gearsets, the 5.08 is the best compromise IMO. I can't imagine needing the 5.72 - the 5.08 is already low enough to pull a house off its foundations, and if it ever isn't low enough, I can always put the t-case in low range. It seems to have the best overall spread in the 1st-3rd ratios. Personally I never have to use 1st gear unless I'm hauling/towing more than 3000 pounds.

The 1.61 3rd gear in the 5.72 might be a tiny bit better for hill pulling with a load than the 1.53 3rd gear in the 5.08. However, with 1st gear being so low, I use 2nd gear for starting from a dead stop 75% of the time, and still have to upshift pretty quick. With a 2.94 2nd gear the upshift would have to be even sooner.

The one with the 4.14 first gear just seems like it wouldn't be as good either because with my 5.08 the 2.67 second gear is just barely low enough for starting from a dead stop without having to slip the clutch excessively. Seems to me like that 2.37 second gear would be just a tad too high for starting from a dead stop in a lot of situations.

So, like I said, the 5.08 seems like the best overall compromise for me.

 

I've got the 5.08 ZF5 also. Having run the T-19d with it's 4.02 1st for 23 years in my '86 F350 w/3.54's, I feel the 5.08 is the best for starting a hvy
load or just tap the fuel pedal and then hit 2nd when empty. 2nd thru 4th
all seem spaced pretty good.

 

You runnin' that 5.08 with 3.54 diffs? I've got 4.10s and sometimes wish I had the 3.54s

1st gear would get a lot more use though...

 

More info for you on the ZF 5.

The S 42 with a 4.65 low gear ratio is rated for 433 ft lbs torque.
The S 42 with a 5.72 low gear ratio is rated for 419 ft lbs torque.

The S 47 is rated for 462 ft lbs for all ratios.

 

i dont have anything better to do