Where can I get GM 3.23 or 3.42 gears for a 3 series carrier? Also, what kind of, if ANY performance gain or MPG loss would i see switching from 3.23's to 3.42's? Car is never at the track, just daily driven, but if there isnt much of a MPG penalty and a slight performance upgrade, then it would be worth it to me. Rear end needs a new gear anyways, as its howling right now, so when I replace everything, im trying to figure out what gear to get. Thanks!

 

Anybody???

 

What gears currently?? 3.23's I'm assuming? (since you stated for a 3-series carrier, and you have an A4? )

If it's howling, it could just be a bad bearing ... I had a carrier bearing go in my factory 2.73 diff, but there was nothing wrong with the gears. If you're happy with the 3.23's, I'd probably just leave them. If you're gonna switch, I'd say go to at least a 3.73, otherwise it's almost not worth it .

But pull it apart first and see if you really need gears, or maybe just a bearing or two (there's 1 on each side of the carrier, and the pinion has 2 bearings ... could be any of them).

 

Well, the rear has 3.23's in it stock and the rear also has 125,000 miles on it, so I figure a general overhaul is better than just new bearings. Its whining and its probably the bearings, but might as well do the whole thing.

 

i would upgrade to 3.73s, you wont be that much higher in RPMs, and there will be a performance gain.
3.23s and 3.42s can be found from
motive
strange
richmond
SLP
even your local chevy dealership

3.73s can also be found from all of those manufacturers.
Check with the vendors on this site, otherwise summitracing.com and fbodymotorsports.com has gear setups

 

Out of all those dealers, whos gears are typically the quietest? I know ive heard that Richmond gears are louder than others usually.