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08-30-2011, 11:56 AM #11
- Join Date
- Jul 2010
- Denver, CO
- Blog Entries
With my 4:56 gears, my 4" lift, and my 34.5" tires, I am still getting about 14mgh city and 18mpg hwy....but I also have it custom tuned and some other mods that help with getting better mileage. I leaned toward the side with a little more power and less mileage, as this is not my everyday driver and I spend a lot of time climbing hills. I'd go with the 4:11s with your set up...I think you'll be happy with the extra power and won't really notice the mileage difference (too much!) .
Last edited by mfleetwood; 08-30-2011 at 12:01 PM.
Mike (Denver, CO) - 2008 Sierra 1500 Z71 SLE 5.3L 4WD
SUSPENSION: Rancho 4" Suspension Lift; Rancho RS9000XL Shocks; Rancho Skid Plates; Rancho MyRide Wireless Shock Controller;
TIRES: BFG All Terrain KO 315/70/17
DRIVE TRAIN: 4.56 Gears; Detroit TrueTrac Differential; True Cool 40k Transmission Cooler
PERFORMANCE: DiableSport Predator Tuner; Custom Tuned by Diablew; Magnaflow Exhaust; AFE Cold Air Intake
ELECTRONICS: Kenwood DNX6180 Touchscreen; Subthump box w/10" Kicker; Driver Information Center (DIC); Rear View Camera
ACCESSORIES: Westin Brush/Grill Gaurd; Westin Nerf Bars; Truxedo Tonneau; 20% Tint; Tow Mirrors w/Heat & Signals
08-30-2011, 01:54 PM #12
- Join Date
- Nov 2010
I do have several other upgrades done to the truck, like a corsa cat back exhaust, banks ram air intake and an edge power programmer. I appreciate the help, but I have 1 more question what size axles are in these trucks now a days both the front and rear so I can start looking at prices. I was considering canning the G80 rear in favor of a detroit e locker
08-30-2011, 09:06 PM #13
4.10. 56's would be way too steep with the 6 spd. Most charts out there do not take into consideration the ratios of the newer 6 spd transmissions. You have an 8.5" 10 bolt.
Last edited by Blackout07; 08-30-2011 at 09:10 PM.
08-30-2011, 09:54 PM #14
Depending on how much freeway driving he does I think 4.56 would be fine.
I used this calculator when figuring my new gears and it was pretty much dead on. I use .70 for the OD ratio...
With 4.56 @ 80MPH it puts him at about 2500 RPM.......his engine can take that all day long.
08-31-2011, 05:48 PM #15
I thinking about regearing and i was looking at the Gear Ratio Chart. I see that with me upgrading to 35's soon next year a 4.56 would bring it back to factory ratio and 4.88 and 5.13 have more power gains. I do drive on interstate a bit and wonder if the rpm's would be up too high for running 35/12.50/R20 20x12 rims along with 4.88's or 5.13's? I assume the 5.13's are too much for highway purposes and think the 4.56's and 4.88's would be better..?
2008 Chevy Silverado Ext. Cab Lt Z71 5.3 V8
7.5 Inch Rough Country Suspension Lift
RBP Replica Grille Black w Chrome Rivets
Recon Smoked Cab Roof Lights
N-Fab Powdercoated Gloss black Cab Length Nerf Steps
5% Tint over 20% all the way around / 5% Eyebrow Strip
AVS Smoked Window Visors
Z71 Stickers Black & Metallic Silver
Tow Mirrors / Smoked Turn Signals
XM Satellite Radio Fin / Color Matched
Interior Plastic Pieces / Color Matched
Power Acoustic Tweeters
Painted Bowties / Color Matched
Painted Door Handles / Color Matched
Smittybilt Bull Bar / Color Matched
Custom Rolled Edge Exhaust Tips / Color Matched
Custom 2.5 Inch Cat Back True Dual Exhaust
Flowmaster Super 40 Series Dual in / Dual out
Magnaflow Tru-X Pipe
K&N Air Filter
18x9 Rockstars Machined Black
Center Caps / Color Matched
33.13.50 Nitto Terra Grapplers
New Front Wheel Well Liners
Eagle Eye Black L.E.D. Tailights
Eagle Eye Black L.E.D. Third Brake Light / Smoked
Eagle Eye Black L.E.D. Halo Projector Headlights
Notto HID Kit 10,000k Low beams
Recon L.E.D. Light Bar
Buschwacker OE Style Tailgate Cap
AMI Gloss Black Antenna
Debadged Chrome Lettering
Door Molding Removed
08-31-2011, 06:28 PM #16
As I've mentioned before on this site I don't like any gear more than a 4.56 in a 1/2ton axle. Because the axle housing is small the ring & pinion have to be small so the when you machine more teeth on the ring & pinion the teeth are thinner in order to get all the gear teeth so when you go over 4.56 the teeth are getting thin. Go with 4.56's.:cool:
2005 Chevy Silverado Z71 Crew Cab
6" Skyjacker lift w/Edlebrock dual front remote resoviour shocks, single rear remote. Rancho skid-plate.
17" x 9" M/T Classic Lock Wheels, 35" BFG A/T or M/T tires
4.10 PercisionGears w/factory locker, T/A Performance rear-end cover
Banks CAI intake, ported throttlebody, JBA coated headers, over-sized Magnaflow cats, Magnaflow cat back exhaust, Diablo tuned
B&M aluminum deep transmission pan
Warn brush guard w/Warn 9.5 XP winch, PIAA bulbs, Line-X bedliner, AWS Black tool chest, Extang tonneau cover
Weather Tech floor mats
Cover-Craft seat covers
Dash mat cover
Formula One window tint
One black Lab in rear seat.
08-31-2011, 07:24 PM #17
Oh okay thanks for letting me know had no clue. I found 4.56 gears for front/rear for around $440 which i guess isn't that bad. I would rather me and my buddy install them i want be paying labor for this! How hard is the install and how long will it take for both front/rear?
I also will buy the Maghytec cover for my rear diff. when i buy the gear's. I plan on buying gears and cover first then buy new tires and rims along with my body lift!
Last edited by Rockstarrchevy81; 08-31-2011 at 07:28 PM.
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