3:73 vs 4:10 gears

[jjakes2003]

New to the forum. I am about to buy a 2004 Sierra 1500 ext cab shortbed w/5.3L and quadrasteer. I had a choice between a vehicle with 3:73 rear end and 16in wheels and one with 4:10 rear end and 17in wheels. I went for the 4:10 because that was the color combination I wanted in the vehicle. I was told that the 3:73 would give me a better or smoother highway experience and better gas mileage. Since the RPM's would be lower. It would be better for the life of the engine as well. I have a 45 to 60 mile commute each day to different locations. Will the 4:10 with the 17in wheels be that much worse than the 3:73 with the 16 in wheels in regard to gas mileage and highway ride?

[cyclejerk]

It'l be worse, but how much I dont know. up to you. I would think that if they are offering it, it will be fine. You never know when you'll have to outrun that soccer mom in her minnie van.

[Wingnut]

The wheel size/diameter will not make a difference, it's the overall tire diameter that factors into the final drive ratio and I would be willing to bet that it's the same on both trucks.

 

4:10s will give you a lot more grunt/getupandgo, but for cruising at 80....You will suck up the gas.

 

3:73 is better (in my opinion) for daily unloaded driving, as well as higher speeds.

 

If your truck spends a lot of time with a heavy load, or towing, I would say 4:10, if not, 3:73.

 

Of course, all you have to do, is put some 305s on a truck with 4:10s, and that would lower the final drive down ratio down a little.

 

Just my .02

[Mule]

I had 3:73 in my Yukon with factory (265/75R16) tires and it was fine. Then I added new tires (305/70R16), and it became a pig. Always downshifting on the highway and lugging around town. When I switched to 4:56, it put it back in the sweet spot, milage nearly doubled (not from stock, but from the big tire/stock gear phase), and it is at the right RPM around town.

 

Given your choices, 4:10 would be a good selection. If you want to increase your tire size, even just an inch, you will be happier with the lower gears.

 

Yes, when I had the 3:73 and 305 tires, I got great highway milage, but it was more than offset in town, or when the highway had a hill or towing, and it had to keep downshifting.

 

Sorry to get long winded, but when I swapped out the 3:73, three shops said going to 4:10 was not a huge leap, I should go 4:56. So, "4:10 with the 17in wheels be that much worse than the 3:73 with the 16 in wheels in regard to gas mileage and highway ride?" I don't think so. Your highway "ride" will be fine, your milage may be a little lower on the highway.

[HillHound]

The 4.10 is great, if not necessary, if you do any heavier towing at all with the 5.3L. I had 4.10s on my Silverado 5.3L Z71 and it got 14mpg mixed driving and as much as 17 highway.

 

Another positive: you'll also find that the automatic will downshift less often at highway speeds, which means less heat and wear on the transmission.

[mdub]

Wish I could trade you... I have 3.73 gears and 285/75/16 (32.8") tires. I would love to have the 4.10s on the highway. The 5.3L doesn't have the best torque, and often needs slightly higher RPM to make it over hills without shifting -- the 4.10s will help with this issue. The mileage may be marginally worse, but I'm sure a very minor difference. You made a fine decision.

[Shaners]

Like everyone else said, the 4.10's will be great if you go +1 or +2 in tire size or if you tow or haul very much.

 

Depending on where you live, if you have alot of hills to go over the 4.10's will give as good or better MPG's than the 3.73's.

 

Higher RPM's may mean a minimal amount of extra wear on the motor, but you are only talking 400-500 RPM on the interstate. The important thing though, is those extra RPM's put the motor closer to the power band where it runs more efficient. For example, if you are holding the throttle steady and lugging the truck up a hill at 60 MPH, and then you pull the shifter into "3", your RPM's will increase and generally your truck will begin to accelerate. You're not using any more gas because your throttle position hasn't changed, but your motor is running more effeciently.

[Hecktorx]

The difference between 4.10s and 3.73s at 60 mph is about 250rpm.

 

Pretty much on the Highway, you will lose a little MPG with 4.10s but in stop and go, it could actually be a little better. With the lower gears, it could also put less strain on the drivetrain when accelerating which could help drivetrain life. But the motor does turn a few RPM higher on the highway which could hurt.

 

So pretty much what everybody else said, there are +'s & -'s to both, but the differences between the two are probably barely noticable for a stock truck. I tow 2000lbs regularly through hills, that's why I went with 4.10s.

 

Kenny

[JayMan]

When I was looking to order, my dealer STRONGLY encouraged me to order the 4.10's, which were a no-cost option. They noticed little if any impact on highway fuel economy, MUCH better performance, better town MPG, better "work" MPG, and better life. They also warned about increased noise/vibration, and let me drive both dealer 3.73's and a private 4.10. A customer in for a wheel alignment was kind enough to let me drive his 4.10 truck.

 

With almost 4 years of experience in my GMC, I can offer the following:

 

1.There is more gear noise and vibration. Lower gears always do that

 

2.Any speed under 75 MPH the MPG should be the same if not more, especially with a strong headwind. I get at least 18 MPG with the cruise on 65 MPH, which is about 2100 RPM.

 

3.Don't even think of towing +5,000 lbs without 'em

 

4.In pure town driving in winter, buddies with 3.73's average 10 MPG, I average 13 MPG.

 

5. If I had to do it over again, I would get the 4.10's.

 

Note: the P265/75 R 16 tire has an outside diameter of 31.5 inches average. The factory "plus one" P265/70 R 17 has an outside diameter of 31.6 inches average. The stock P245/75 R 16 tire has an outside diameter of 30.4 inches average.

[Wingnut]

3.Don't even think of towing +5,000 lbs without 'em

I will agree that 4:10's are a lot better for heavy loads (see my post above)

 

-But-

 

I do it (tow up to 6k lbs) all the time, and I have 3:73s in both my rigs.

 

Doesn't hurt them one bit.

 

My 92 will even pull it without breaking a sweat.

 

But gas mileage is in the tank....So to speak.

[CapnDean]

Are ya ready for the why didn't I think of that?

 

Please tell me that the technology exists for a 2 speed rear axle?

 

Wouldn't it be the BOMB to have say a 3:08 ratio for the road and a 4:56 for the load, and the ability to choose between the two from the cab?

 

So what you gotta come to a complete stop. So what you have to do it before you drop her in gear...it wouldn't even need to be shift on the fly technology.

 

Just think how nice it would be to be able to choose mileage OR performance whenever you needed whichever!

[JayMan]

Are ya ready for the why didn't I think of that?

 

Please tell me that the technology exists for a 2 speed rear axle?

 

Wouldn't it be the BOMB to have say a 3:08 ratio for the road and a 4:56 for the load, and the ability to choose between the two from the cab?

 

So what you gotta come to a complete stop. So what you have to do it before you drop her in gear...it wouldn't even need to be shift on the fly technology.

 

Just think how nice it would be to be able to choose mileage OR performance whenever you needed whichever!

 

Oh sure, that's only been around for 50 years or so!

 

Like a Double Reduction axle in a commercial truck. Yes, you can shift on the fly.

 

Gear Vendors makes a two-speed over/under or double under that bolts behind the trans. In a 2WD, this effectivly doubles your low gears, and/or adds a super overdrive for empty. You turn a 4 speed auto into an 8 speed, or a 5spd stick into a 10 spd. Can also shift on the fly.

 

This technology has been around forever, and is proven in heavy commercial use, but maybe the manufacturer thinks we're too dumb to deal with an extra lever on the floor.

[Wingnut]

Or that we would remove the rev limiter, go with a super-high ratio, and try and break the sound barrier in a 1/2 ton Chevy.

 

Also, I know I'm probably wrong about this but...Doesn't 4lo, and 4hi effectively do the same thing?

[jjakes2003]

To all who responded to my post. I wanted to say thanks for the great info. It certianly is great to be able to ask questions and get the voice of experience back. Thanks for the info it is all good!

[HillHound]

Higher RPM's may mean a minimal amount of extra wear on the motor, but you are only talking 400-500 RPM on the interstate.

Shaners,

 

From what I've seen, the rpm difference between the two ratios in OD @ 70mph is usually only a little over 200rpm.

 

My philosophy is it'll cause a little more wear on the engine but a little less wear on the transmission due to less shifting on the highway where most of the mileage is racked up. Which is likely to fail first?

 

I'd say the transmission, so the way I look at it the 4.10s may actually be the best bet if you're worried about wearing something out.