poopshovel again said:759NRNG said:2010 CTS-V M6 .....on my fourth diff... don't ask....recent trip home from D'Iberville Ms. to Decker Prairie Tx. saw 20.5 mpg...I'll keep it....now let's see about some new tires...
2010 CTS-V AT. Can I ask anyway? I’m getting a weird noise shifting from 3-4, and it doesn’t sound like it’s coming from the trans.
Best I’ve managed is about 1 liter per hectare.
If the noise modulates with throttle input could be the beginning of a $3500 repair(dealer) .......I would have attempted to fix this myself, but was 700 mi from home 
. When was the last time you had the diff fluid changed? Also I went to the ctsv owners forum (beware they don't take kindly to first timers btdt) for my situation. Scoured the posts and found info describing my predicament.....the consensus is the fluid from GM with the friction enhancer is the way to go.....This fourth diff was installed at Preston-Hood and I insisted that friction modifyer(BG) be added, I now have 3k on this diff (break-in) and will be changing fluid this weekend .
