05 2500HD 6.0 4X4 ECSB What Gears?

[SGP93GSX]

Hey all,

I am running an 8" lift with 37" Tires on 20's. Right now I have 4.10's. Lost acceleration. Pulling power is down. First I am looking to swap gearsets. Looking to get a tune. Then possibly go to a front mount turbo with supporting mods. My question is, with what I am looking at in the future, would you go with the 4.88's or 5.13's? Looking to help MPG and help all around.

[DAmarcus28]

i think 4.88s would do the trick

[foggy]

I run 4.88's with 35's getting 10-11 mpg.

[BigMac]

You have aerodynamics of a barn door and are rolling on an additional 400lbs of rubber and steel. Gears aren't going to help you that much my friend. Where you're at, low gears will kill you on the highway and tall gears will be lugging like crazy in town. Money spent on gears will not pay for the difference, if any, that would be saved from any increased mileage. I've been through 4 lifted trucks and several offroad rigs. While gears are a good idea for the right reasons, better pulling down low, they are not the saving grace for fuel economy.

[SGP93GSX]

Gears aren't going to help you that much my friend. Where you're at, low gears will kill you on the highway and tall gears will be lugging like crazy in town.

BigMac,

I guess really I am trying to get the drive train back to seeing a "stock" load as far as diameter of the tires/wheels. But also looking to set the truck up for a turbo. As I have been reading the turbo likes to be "loaded" Hence the question on the 4.88/5.13.

I do use the truck for work. It has to pull a load. It does OK right now but not like I want. The gears will help unload the drive train and put the strain on the axles more so than the transmission and drive shafts. For me axles are much easier to replace.

Keep the comments coming. That's why we are all here. To learn from others experiences. Whether we like what we are being told or not.

Thanks

[BigMac]

I pondered the whole gear swap idea several times on my rides but it costs twice as much for us to do it since we're 4WD. I have found a few online gear calculators so you may want to do a search for that, I'll let you know what I find. I think it was from 4wheeloffroad.com or something like that. For your jump in tire size I would go with the 5.13's, but this may be in the high RPM range for highway use. I ran 4.56's with 35's and had no problems.

[tanz45]

Check out Rons. Great package deal prices on gears.

[SGP93GSX]

Check out Rons. Great package deal prices on gears.

Sent a PM to Ron Yesterday

[1978steven]

I run 4.88's with my 20X10's and heavy 37's and couldn't be happier. They put me a bit over where my truck was with the factory gear set and factory tires which is good because IMHO these trucks like a bit more gear....

4.88's with 37 inch tall tires and factor in your .75 overdrive @ 70 MPH should put you around 2327 RPM.

5.13's with same as above should spin you up an additional 119 RPM pushing you up to 2446 RPM.

Ron's Machining Service is where I also got my gear sets and Detroit TT, great guys to deal with....

[Silverado05]

Gears will do alot of difference, I went from 3.42s to 4.56s on 35s. But ill tell you something 4.10 to 4.88 will not do that much difference.