I have an 05 GMC Sierra SLE, factory 3.42s. I want to go up to 4.10s, a local guy has a front diff out of a 99 Z71 NBS that he parted out. Will it work? Are there any differences between years? I have been told that the transfer cases changed around 03-04, true? I feel like I would rather swap out the front diff vs. pulling mine and taking it somewhere to get the ring and pinion changed.

 

It will fit but the one from a 99 probably has a floor shifter and yours is electronic shift, better off finding an exact replacement

 

Should be a plug and play swap. Whether floor shift or not, all the front diffs are electric, unless AWD

so to clarify; 4wd diffs are all compatible, AWD diffs are the odd duck