I tinkered with my direct injection 12valve turbo and upped the boost to 28lbs. There was enough power to operate 1to0.85 gear ratio 5th gear to motor around city streets and slow free way traffic easily. Unfortunately until I tack welded it spun off twice setting 5th free. We tried a Spline nut with a retaining bolt. The spline nut broke.

The first tank of fuel with the 1 to 0.73 5th gear was 600 miles carrying a load of 1500 lbs of people, dogs, wood, equipment and feral hog.

 

As far as HP ratings.. Iv been told the NV4500 can't handle big numbers.

Im looking at replacing my blown 1990 6bt with a built 1994 donor with more than 500 hp. Buying the entire truck for the axles etc.

Can my nv4500 (welded nut) handle 600 hp? Or should I convert my rig to the donor built 47RE and run that? I really don't want to run the auto, but will run what ever is the most reliable for towing 8k#.

Thanks

 

The NV4500 is the same transmission as the one in the 3500. The load differential is in the Rear end gearing. Most 3500's have around a 4.10/4.11 style. The thing that will wear the most is the clutch. Going with a heavier duty one would be wise at your next opportunity.

My cousin found a machinist to retool his transmission gear spindle. The factory nut going up against the 5th gear is a Righty-tighty. He had the shaft retooled to a Lefty-Tighty. He has not had any problems since. He has 400K on his 3500.