many peeps have done a getrag to nv4500 conversion
http://www.quad4x4.com/Getrag to NV4500 conversion.htm
The NV4500 transmission is a heavy duty 5 speed overdrive transmission. The 4500 is readily adapted to many vehicles that originally were equipped with light duty 5 speeds, 3 speed manual transmissions, 4 speed manual transmissions or automatic transmissions. The transmission has a cast iron main case, large gears and weighs approximately 200 pounds. NV4500 transmissions are original equipment on both Dodge and GM vehicles up to one ton. The transmission was introduced during the 1992 model year and still remains in production.
Manual transmission to manual transmission conversions usually require at least a new bellhousing and clutch lever. For most applications a new transmission mount, clutch assembly and transmission to transfer case adapter will also be required. Modifications to the crossmember, floor pan, driveshafts, and exhaust system are needed for some applications. Parts costs for the basic adapter kits start at about $350 with an average cost of about $650 plus the cost of the transmission.
Automatic to NV4500 conversions are generally much more expensive due to the numerous additional parts you will need. Figure on a new flywheel, flywheel bolts, clutch assembly, clutch bolts, bellhousing, clutch fork, clutch release system, clutch pedal, brake pedal, transmission mount, transfer case linkage, and hardware. You will need to cut the cab floor/carpet to accept the shift tower, rewire the backup lights and cruise control. Late model vehicles may require major electrical changes including changing the engine computer. In most cases you will also need to have driveline modifications done. Some models will also require crossmember and/or exhaust fabrication and/or relocation. Body lifts or cab floor alterations may be needed for clearance. Unless you have a donor truck to cannibalize most or all the parts from, this is usually one expensive conversion. NV4500 conversions for gas engine trucks will typically run from $3500-$5,000 for all new parts including the transmissi