I believe the THB W 166 1 E sequence decodes as

THB = 1971 1/2 ton 3.07:1 ratio (3.73 was standard, 3.07 optional)
W = Warren, Mich (plant)
166 = June 15 (166th day of year)
1 = Dayshift
E = Eaton positraction differential

Found the THB reference here:
http://www.americanclassic.com/paint.htm?p1=axles

Used the site sequence example for 71 and later axles to decode the rest:
http://novaresource.org/axle.htm






"Nothing astonishes men so much as common sense and plain dealing." - Ralph Waldo Emerson