I wasn't familiar with the NV4500 so I went to Novak's site and did some reading. Although those folks are primarily focused on the Jeep market, their general appraisal of the NV4500 was not very good.

They cited very high initial cost and expensive repairs to problematic innards along with ratios that weren't real "big truck friendly".

I have no first hand experience with this transmission, but the 5th gear OD sounded pretty neat...Novak says this is one of the problem areas of the NV4500 too!

Stuart