If you like your highway mileage stick with 4.10s.... I miss mine.
But the 4.56s sure make it fun to light up the 35's
If you like your highway mileage stick with 4.10s.... I miss mine.
But the 4.56s sure make it fun to light up the 35's
MKader17
I have 4.88's on 35's and at 70 mph push 2500 rpm, but I plan on 37's! I'd say 4.56's, but 4.10's will get the job done.
Edit:
I used one of those rear gearing calcs online, to be exact I'm at 2296.48 rpms at 70 mph with the 35's. Kinda hard to tell when your looking at the gauge and it might be off a touch, who knows....
Last edited by 1978steven; 04-20-2009 at 01:41 PM.
2002 Silverado 2500HD LB7 CCSB LT
EFI Live by Rob at ATP, Edge CTS Insight DSP 5 control, S&B CAI, PPE boost valve, Pro Fab AIH, AirDog II 165, PPE WIF sensor delete plug, 5" stainless exhaust, Cognito braces & HD tie rods, H2's 315/70 R17 BFG's
2004 Tahoe LT
2006 Silverado Z71 LS
1971 Chevy C10
4.56 or don't even bother with it
Let me tell you what Melba Toast is packing here allright............
haha well i definately need something different from my 3.08s i am just afraid of killing my mileage thats all and its pretty split half and half. I think i will go with 4.10s but just out of curiosity what do you guys run for rpm's at highway speeds? Thanks for all the help
I turn 2296.48 running 70 mph, that's with 35's, 4.88's, and the 4L60E tranny. There is a decent calculator at: Transmission / Rear Axle Gearing the only thing is, it only goes up to 4.56 gears, but I think 4.88's would be overkill unless you plan on going bigger.
With the 4L60E, 35's, and 4.10's running 70 mph you'd be at 1930 rpms. With the 4.56's running 70 mph you'd be at 2147 rpms. Not a huge difference, but throw a trailer behind it and you'd want the 4.56's, for the torque!
2002 Silverado 2500HD LB7 CCSB LT
EFI Live by Rob at ATP, Edge CTS Insight DSP 5 control, S&B CAI, PPE boost valve, Pro Fab AIH, AirDog II 165, PPE WIF sensor delete plug, 5" stainless exhaust, Cognito braces & HD tie rods, H2's 315/70 R17 BFG's
2004 Tahoe LT
2006 Silverado Z71 LS
1971 Chevy C10
just do the 4.56, be much better and your tranny will love you more
Let me tell you what Melba Toast is packing here allright............
Thanks for all the help guys and that website was also helpful. 4.56s it is.
Your pinion gear is gonna be tiny, and weak. I hope you're not gonna pound on it too much.
2001 ECSB 4x4, 5.3, Radix, 3.0 pulley, VHP Trucker cam, 216/224 .551/.551 115 lsa, 1.8 Crane roller rockers, 4L65E, Yank SC3000, 3.73, Cal-Tracs, HPTuners.
The pinion gear on the 4.56's is a great deal smaller than the pinion gear for he's factory 3.08's, but the 10 bolt by itself is very weak unit. For daily driving and occasional offroad use he'll be fine with the 4.56's. Alot of the lifted guys run 4.88's and 38's and do just fine daily driving and some offroad. Now, get up to the 5.13's in a 10 bolt and you'll snap a pinion under heavy torque quick as hell. You could always upgrade to the 14 SF later down the road....
2002 Silverado 2500HD LB7 CCSB LT
EFI Live by Rob at ATP, Edge CTS Insight DSP 5 control, S&B CAI, PPE boost valve, Pro Fab AIH, AirDog II 165, PPE WIF sensor delete plug, 5" stainless exhaust, Cognito braces & HD tie rods, H2's 315/70 R17 BFG's
2004 Tahoe LT
2006 Silverado Z71 LS
1971 Chevy C10
I have a set of 3/4 ton axles laying around i just don't want to buy new wheels.
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