The $600 is just an estimate and is for just the parts required for a new rear (labor will be more). If you want to purchase the unit yourself you must know what the gear ratio is, what size the differential is, and how many splines there are on the axle. It is most likely an 8.5 inch rear but you should go to the drivetrain specialists web site. There you can see what is involved with identifying what rear you have. You can also purchase everything you need there. You must also decide what type of traction you want - limited slip or posi. If installing a new unit, I suggest going with a Trutrack with the new stock gear ratio ring -n- pinion and a timken bearing installation kit. If you do not know how to install this init I suggest having a professional do it. DTS has instructions, but if you don't know what you are doing you can easily mess it up. Once again, driving this blazer will lead to more damage.
BTW - be aware when purchasing a new ring -n- pinion gear set. There are different manufacturers. O.E.M. Is the quietest gear set and I suggest O.E.M. But if you are planning on going off roading and stuff like that then Richmond - U.S Strange - AAM gears are what you want. Motive Gears are junk.
Sunday, January 10th, 2010 AT 9:24 PM