Output mostly so I don't risk ripping my tcase in half if I gave to use 4wd on grippy stuffWhat specs are you looking for exactly?
Okay awesome, thanksPretty sure factory numbers are 365hp and 660tq
The duramax/allison is paired(from GM) with an NP261xhd manual or 263xhd electric case, they have specific larger diameter 31spline shafts vs the more common smaller 32spline.
At 440k you need to rebuild the turbo,replace the injectors, glow plugs, and cp3 pump, replace the water pump and while you are at it do both the front and rear main seals. Remove the air horn and intake bridge and clean it out. Replace the fuel rail pressure sensor.
I'd consider doing head gaskets as well..
https://www.amazon.com/NP261XHD-NP263XHD-Main-Shaft-Spline/dp/B07GZ5V299They use a 29 spline, not 31 or 32 spline.
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https://www.amazon.com/NP261XHD-NP263XHD-Main-Shaft-Spline/dp/B07GZ5V299
I was referring to output shaft splines