Gears..

ColoradoSkiCountry · March 23, 2008

Alright folks help me out here. I know quite a bit about trucks but when it comes to the gears.. I'm clueless.. 4.10.. 3.73.. I've had 2 trucks in my life, a 99 Silverado Z71 5.3L which was a great truck, and my current 2007 NBS 5.3L Z71. I have noticed that my 07 "winds up" a bit more RPM wise when going through the gears, compared to my 99 which was a crisp and quick acceleration and gear change (both autos) With this being the case, is it safe to say that my 07 has a different gear ratio then my 99 did? I sure did appreciate the quicker crisper and smoother shifting my 99 had compared to my 07 which will wind up, not something I really like.

Any thoughts?

svensk · March 23, 2008

The truck that winds up the rpms faster should be quicker overall. Check your glove for codes of gt4(3.73), or gt5(4.10) gears. You don't want taller gears in a truck really so running at a little higher rpm keeps you constantly closer to the peak power band. I have 3.73's, but with my bigger tires I wish I had 4.10's. When cruising the highway in OD at 70mph you should be at around 2000rpm.

ColoradoSkiCountry · March 23, 2008

The truck that winds up the rpms faster should be quicker overall. Check your glove for codes of gt4(3.73), or gt5(4.10) gears. You don't want taller gears in a truck really so running at a little higher rpm keeps you constantly closer to the peak power band. I have 3.73's, but with my bigger tires I wish I had 4.10's. When cruising the highway in OD at 70mph you should be at around 2000rpm.

THIS was the message!!!

Thanks for the info

ColoradoSkiCountry · March 23, 2008

in OD at 70, I'm at about 2300 RPM

Starrman · March 24, 2008

you probably have 4.10 gear then. Look at the sticker in your glove box for the 3 digit codes listed above

svensk · March 24, 2008

in OD at 70, I'm at about 2300 RPM

Montana Bronco · March 26, 2008

From your handle, I take it you are in "Colorado ski country".

Well, I am in Montana Ski Country. Same terrain.

Up here in the mountains you want 4.10's.

05silvycrew · March 26, 2008

you definitly have 4.10's, that's the RPM's I tach when I'm going 70ish.

It's a great gear for towing, or running up and down hills/mountains, or even on the highway (55-60MPH). But, once you get above 60 MPH the gas mileage really drops off.

55-60 MPH i see around 18-19 MPG

70 MPH i net around 16-16.5 MPG

I wish GM offered a double overdrive option for trucks with 4.10 gears

flatlander · March 26, 2008

Have had three Silverados, two with the 3.73 gears & one with the 4.10's. Two of them had the same 265/70x17 tires so I can give a comparison between those two. At 70mph the truck with the 4.10 gears seemed to be running a little over 2200rpm while the one with 3.73 gears is very close to 2000rpm. So it's only about 200rpm difference. It is hard to tell exactly what RPM's the truck is running but this is my best shot at it. My preference would be the 3.73's as I have gotten the best gas mileage with that combination. Seemed like when I drove the 4.10's at highway speeds the mileage dropped off more than with the 3.73's. Have not found power or lack of it to be a factor and yes, I have driven in the mountains of Montana on several occasions. Just my 2 cents.