working on a 99 s-10 ls rear end is growling bad well bc of time and tools really like to just replace the whole rear end ...no one has a 4wd with 4 wheel disc and abs really like to know what the differance is between the 2wd rear end and the 4wd rear end

If you're going into a 4WD, the axle ratio MUST be the same as the front differential. 2WD could have disc or drum brakes. On 4WD disc were standard. ABS sensor is in the transfer case on 4WD and in the transmission on 2WD.