I will start with the drive train. We had the NP203 rebuilt using
a full master rebuild kit (every seal, gasket and roller bearing). While it was
apart we had them install a Mile Maker 501 part time kit and a TH400 input shaft.
I was told that being a reasonably handy monkey of the grease sub sect, I could
rebuild the T case myself and for the next truck I will. I have the exploded diagrams,
and enough patience to get the job done. Now on to the next challenge (hooking
the NV4500 to the NP203). Every one who I asked who has done this did it in a
different way.
This is the rout I have chosen. The output of the NV4500 transmission
is a TH00 with the Chev 4WD tail section.
Chevy tail section
The new NV4500 with the Chevy Tail Section
The bolt pattern for tail section was going to drilled into the fount surface of the NP203 however the T Case was out for rebuild when the Transmission arrived. So in order to follow this plan we would have to disassemble the front of the 203 and drill the outer case.This method gave us about 2.6 inches of spline engagement.
The NP203 front face
Chevy tail section
The new plan (which dose not involve disassembly of the 203 internals) is to remove the old NP203 to NP435 adapter and machine it down to an adapter plate. The bolt pattern for tail section will be drilled into the adapter plate.we will loose about 1/2 inch of of spline engagement from the thickness of the plate.
So this method gave us about 2.1 inches of spline engagement.
NP203 to NP435 adapter
Every thing below the red line get cut off and what left on the casting gets milled down flush with the plate.
