The 3.42 vs 3.73 Rear Axle Ratio: What Are The Differences?

Many car enthusiasts are familiar with the 3.73 ratios regarding axle ratios. However, most people don’t know that the 3.42 axle ratio also exists. The 3.42 axle ratio is designed for touring or highway driving. 

So 3.42 vs 3.73 rear axle ratio, what is the difference? The 3.42 axle ratio has a shorter diameter for a full turn compared to the 3.73 axle ratio. This ensures a decent fuel efficiency while 3.73 provides quick acceleration. 

Regardless of which axle ratio you choose, check the corresponding gear ratio to ensure it’s compatible with your car’s suspension and axles. So read on to learn all you need about this important decision.

What Does A 3.42 Axle Ratio Mean?

Axle ratio 3.42 means the driveshaft revolves 3.42 times in one wheel turn. This will result in a higher cruising speed on the highway but slow progress in acceleration. 

Vehicles with a lower axle ratio like 3.42 will hit a higher cruising speed but will not accelerate as fast as those with a higher axle ratio. This gives you better fuel economy. 

What Is A 3.42 Gear Ratio Good For? 

The 3.42:1 Gear Ratio is often referred to as the ‘gold standard’ for car transmissions for a good reason. It provides optimal fuel economy while maintaining high reliability and performance. 

This gear ratio features a lower first gear than most transmissions, allowing your engine to rev higher to reach its full power potential while reducing drag and noise levels. 

What Does A 3.73 Axle Ratio Mean?

Axle ratio 3.73 means the driveshaft revolves 3.73 times in one wheel turn. The higher the axle ratio, the more cargo a vehicle can carry and the more power it will have.

The greater the torque and acceleration, the easier it will be to move things. And the vehicle will use a balanced fuel while doing so.

What Is A 3.73 Gear Ratio Good For?  

A 3.73:1 Gear Ratio has been a standard transmission gear ratio for high horsepower and torque vehicles. That ratio generally corresponds with faster acceleration because it allows more RPM. 

Soaking up extra miles on rural roads or low-speed city streets might be worth it if you plan on cruising around in top gear most of the time. Leading to balanced fuel efficiency and reduced emissions. 

3.42 vs 3.73 Rear Axle Ratio: Comparison Chart 

If you’re wondering which Rear Axle Ratio 3.42 vs 3.73 is best for your vehicle, our Comparison Chart can help you make a decision. Both ratios provide great all-around performance, but there are a few key differences.

3.42 Axle RatioVS3.73 Axle Ratio
3.42:1Gear Ratio3.73:1
Moderate AccelerationHigher
Increased PowerModerate
ModerateTowing Capacity Increased
7,700 lbs (3,500kg)Load Weight9,900 lbs (4,500kg)
IncreasedCruising SpeedModerate
ImprovedFuel Economy Balanced 
GMC Canyon V-6, GMC Sierra 1500Vehicles Chevy Silverado, GMC Sierra 0.5 ton
ZG GM8.5-342US Standard GearZG GM8.5-373

What Are The Differences Between 3.42 And 3.73 Rear Axle Ratio?

Choosing the 3.42 rear axle ratio vs 3.73 for your vehicle is important. This will depend on what you are looking for from your vehicle, Efficiency or Performance. 

Different gear ratios work best for different people. You need to find the gear ratio that fits your needs and drives you the way you want to be driven. 

Acceleration time

When it comes to acceleration, many factors come into play. For example, the engine and transmission may provide a certain level of acceleration.

But other things like the rear axle ratio can also affect how fast the vehicle will go. A 3.73 rear axle ratio on the same engine will accelerate a car more than a 3.42 ratio. 

3.42 RatioVS3.73 Ratio
Not so QuickAcceleration timeQuick Response 

Power output 

The power figure on a vehicle’s rear axle ratio is important because it affects how much power the axle can give to the wheel at the same time it’s busy accelerating. 

A lower rear axle ratio (3.42) means the axle rotates less, giving the wheel the same power. At the same time, a higher rear axle ratio (3.73) is busy accelerating the vehicle. 

3.42 RatioVS3.73 Ratio
Better but SlowPower OutputModerate but Fast

Torque on the wheels

A different rear axle ratio on a vehicle can change the amount of torque it produces.  A vehicle with a 3.73 axle ratio will produce more torque 

than a 3.42 axle ratio because it increases RPM at high ratios while a low ratio manages it at low rpm.

3.42 RatioVS3.73 Ratio
Moderate TorqueTorque FigureHigh Torque

Towing Capacity 

The Towing Capacity of the High ratio is higher than the Low Ratio. Generally, a 3.0l v6 engine with a 3.42 rear axle ratio can tow 7700lbs, while a 3.73 rear axle can bear a load up to 9900lbs. 

3.42 RatioVS3.73 Ratio
7,700 lbs (3,500kg)Towing Capacity 9,900 lbs (4,500kg)

Cruising Speed 

The 3.42 vs 3.73 rear axle ratio gives us different options for how to use the vehicle. For example, a better cruising speed on the highway with a low ratio axle or heavy-duty work on urban terrain can be chosen with a high ratio axle. 

3.42 RatioVS3.73 Ratio
High Cruising SpeedLow Compared to 3.42

Fuel Efficiency 

When it comes to fuel efficiency, you want to ensure that your vehicle has a rear axle ratio that is as low as possible. A 3.42 rear axle ratio, for example, is significantly lower than a 3.73 rear axle ratio.

And it will be much more fuel-efficient. This is because a vehicle with a 3.73 rear axle ratio will need to travel a significantly longer distance to achieve the same fuel efficiency level as a vehicle with a 3.42 rear axle ratio. 

3.42 RatioVS3.73 Ratio
More Fuel-EfficientFuel EfficiencyBalanced 


Many people are wondering if there is a big difference between 3.42 vs 3.73 rear axle ratio in terms of performance. The answer may surprise you – the differences are minimal. 

So, if your vehicle requires performance, go with 3.73 instead of 3.42 gears. At the same time, the 3.42 ratio does batter in lighter vehicles, such as subcompacts and midsize sedans. 

There is no definitive answer to the question of which axle ratio is better. It depends on your specific needs and what you plan to do with the vehicle. You should choose the option that best suits your needs.

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