Hmm...
www.sacusa.com pricebook say´s that basic overhaul for a MRGB is $7.914.78.-
And that is the absolute minimum if nothing else in the gearbox needs to be replaced.
I think Cross-eyed that your price of "Main Rotor Transmission 3000hrs $6300" is a bit outdated!
"edited: ohh sorry just now saw that your prices were 2003 prices
"