Hello i have a 1999 blazer with a blown rear diff and replaced the whole rear end with a 2001 blazer.The question is what if the front diff ratio is different than the rear? would this f the transfer case when i 4x4? when i bought the replacement from the wrecker he said it was compatible but he was a bit of a clown so now im not sure.

 

yes it will, and your vehicle wont handle at all. and won't want to roll as the front or back would have to spinn faster or slower then the other

most common is 3.42's you will likely be the same.

 

yea he's right check your rpo codes in your truck in the glove box look for either gu6 or gt4, gu6 is 3.42 gears, and gt4 is 3.73, not sure how you can check the rear gears unless the dude from the auto salvage knows the specs to the blazer it came off of.

 

it'll run and drive fine.

Unless you put it into 4wd

 

Had a truck like this while I was swapping axles. I only used 4x4 when I got stuck in the mud. Basically if u use it on the street it'll just be like holding down the brakes