Go to Bill's site and do some reading,
http://www.greatbasinrovers.com/.
You should also go to ,
https://www.expeditionexchange.com/tractech/
and read up om the True Tracs and Detroits.
Round numbers on a Detroit and axles are $1400 plus labor.
I have been running a Detroit/T.T combination for 4 years and really like them.
Mike