Ford uses a different bolt pattern.
At some point in the last 5 years or so, the S10's could be bought with disc brake rearends. Not on all models though. I think 4.3L 4x4's...
To tell if it 2wd or 4wd, just measure the overall length, the 2wd is way too short at around 53" wide if I remember correctly, the 4x4's are about 57" wide...
