If you want to learn how to quiet your ride, spend 30 minutes reading on this site.
http://www.sounddeadenershowdown.com/
The common old school solution was to slap a bunch of layers of dynamat down everywhere.... however the best performing solutions use a variety of materials to address the source and type of noise you are trying to reduce.
They sell a full kit for the Land Cruiser at around $750.
Mine just arrived!
I'll second sounddeadenershowdown.com 'kit.' I'm about 95% through on my '96.