8 3/4 rebuild is this bull shi@&$?

[Kenflo]

Here is a quote from a local shop that I sent an email to. I have a 489 case with cone sure grip and 4:56 ratio. I asked the shop for an estimate to rebuild the center section with a new set of gears 3:23 and freshen up the sure grip if needed. This is what the guy at the shop said:
"The problem with changing the ratio so drastically is that there may be a carrier break. 3:73 and down or 4:10 and up. If that's the case than I need to change the carrier to get the right deck height. "
I am unsure about this issue with a case break! Can any body chime in on what this is? Or is it total bull??

 

[Supershafts]

That particular diff doesn't use a carrier break, but still may need a new carrier if that sg is worn. To be honest id change to a TT while doing the change now

 

[mguner]

What he's trying to say is some rear axles like Dana 60 and 8.25 Mopar use a different part number carrier depending on gear ratio to compensate for the offset from the pinion. 8.75 just uses a thicker ring gear and some use a spacer. The "break" being which ratio range you are wanting to use.

 

[AJ/FormS]

And just to throw a monkey wrench in; 3.23 chunks are cheap. You could buy one and stick it in, then sell the 4.56er, and probably do better than break-even.

 

[MRL Performance]

And just to throw a monkey wrench in; 3.23 chunks are cheap. You could buy one and stick it in, then sell the 4.56er, and probably do better than break-even.

That's what I did. Changed out my 3.55 in my Dart for a 2.94. Found a good complete center section, swapped them out and made $100 in the process after selling the 3.55.