My transmission guy says my NV4500 in my '99 is just plain worn out. He has been into it 3 or 4 times over the last 10 years and now he says I need to look for another one. Allstate Gear in San Antonio sells a rebuilt and updated NV4500 for $975 plus exchange ($500 core). They also sell a newly built one for $1695 with no exchange. They are both built in-house from parts made in Taiwan and both carry a one year unlimited mileage warranty. Thoughts?