From the TCCOA website which BTW does not even mention 4.10 in their debates:
3.27, 3.55 or 3.73 gear ratio ?
If you are considering changing your gear ratio consider this:
If your car has the wide ratio 4R70W tranny, you should definitely recommend 3.55 gears or even 3.27 if you do a lot of highway travel. Your car already has a low first gear, going with 3.73s would probably create a lot of off the line wheel spin. Gas mileage decreases should not be too drastic maybe 2 or 3 mpg's, and you will really only notice that on the highway, not in town unless your right foot gains ten pounds
The top end will be reduced, but that can be fixed with the Chip.
You'll feel a lot more pull on the bottom, but the top will come in sooner as well. You'll need to get some real meat on the rear wheels to maintain traction. I would not run a tire "shorter" than stock.
3.55, while less quick, would probably suit you if you were concerned about the freeway miles (Plus, you may not need a chip with 3.55)
Overall you end up spinning the motor more to go the distances you used to (i.e. more wear), but IMHO the performance difference is well worth it. Once you are in traffic & get that first open opportunity to punch it from 50 to 70 you will know you made the right choice! Good basic maintenance will negate any additional wear.....
Cost ?
In my experience you can expect to pay anywhere from 500-700 dollars (parts included-$180 for gears, $200 or so for install, $220 for a Superchip.) for a good quality installation job. Also, the tolerances in the differential must be kept exact, so you should definitely have it done professionally.
One other thing you might want to consider is changing the speedometer gear to correct the speedo, as it will be thrown off when you change your gears.
BOTTOM LINE from Kilgore: The 4.10 gear with 4R70W means you wil run out of first gear way too quick.
. With an auto you should defiantly go with 4.10s. I don't think you will feel much of a difference with the 3.73s. I have 4.10s and love them(mines a manual) and did not see much of a decrease with gas mileage either so either way you should be ok on gas mileage.
