Service dept told me today if I replace my open diff w/ used oem vlsd, it would voide the ol' warranty...

wtf?

 

yes, its called modification!

 

it would only void the diff
http://www.ftc.gov/bcp/conline/pubs/.../warranty.shtm

 

Ah yes sir, anything not dealer bought and installed should do it. You must always be on the same page as them to be under warranty.

 

yes, but they also told me if I install the Nismo LSD it wiuld still be covered...

 

they are wrong! Believe S tune or R tune forget which ones ARE NOT covered!

 

Lets say that you replaced the differential, then had problems with the motor. How does the differential cause motor problems?

 

They void that portion of the warranty, You know this David!

 

True. But I wanted the OP to use some common sense here.

 

I know, I sense the sarcasm,

Dam you have 18K posts now, WTH have I been, lol!

 

Unlike me - you probably have a life.

 

r tune=no warranty s tune=3 yr 36,000(i think)

 

Things directly attached or closely mouunted may not be covered say drive shaft or half shafts as installation of a diff can cause changes or errors in alignment and thus wear of U or rear CV joints bushings or bearings.

If things that don't usually fail in 150k start failing way early after a modification you can't blame Nissan Warranty for try to exclude warranty on things attached to diff.