It's a 4x4 so you have twice the gears to deal with.
You'll have to modify the gearing in the ABS Computer if it's an allowed gearing and the PCM. You can likely change the gearing with a Tech 2 if 3.73:1 was an option on that computer.
I think I'd change the engine oil cooler lines while the front axle is down. Access will be much easier. If you have an oil pan leak I'd get that at the same time.
Eric O from South Main Auto did a YouTube video on installing new bearings in a T800 front axle while re-using the gears. They're a little more fiddly than a straight axle but not impossibly obnoxious. New gears means you get to measure pinion depth and probably use two or three crush sleeves in the process... and I bet setting the end play is a real fun job too.
You can bump up the numerical gear ratio slightly by using smaller OD tires but this is a truck you want to use as a truck so lowering it with smaller tires isn't really a good option.
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1959 M35A2 LDT465-1D SOLD
1967 Dodge W200 B383, NP420/NP201 SOLD
1969 Dodge Polara 500 B383, A833 SOLD
1972 Ford F250 FE390, NP435/NP205 SOLD
1976 Chevy K20, 6.5L, NV4500/NP208 SOLD
1986 M1008 CUCV SOLD
2000 GMC C2500, TD6.5L, NV4500
2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263
2009 Impala SS LS4 V8
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