D30 carrier break (how to tell the difference)

i have two carriers. one w/ 3.55. one with un known gears. i want to gear to 4.10 and know ill need a new carrier. im not sure what ratio is on the carrier i just got ( it was free from a friend) how do i tell if it is the right carrier or not?

Look at the flange where the ring gear bols on. This should be offset differently to accomodate the thickness of the gear set. If its the same you need a new one.

You can also just buy "thick" 4.10's from places like Randy's Ring & Pinion

Don