When it comes to off-roading in a 5th Gen Toyota 4Runner, one of the most impactful upgrades—beyond tires and suspension—is re-gearing. Many 4Runner owners running 33s, 35s, or heavier overland setups eventually realize that the factory 3.73 gears just don’t cut it anymore.
- Fun fact… while the VAST majority are 3.73, there are some VERY rare examples of 2WD 4Runners with factory 4.56 gearing. The more you know!
That’s where 4.88 (and 4.56) gear ratios come into play. Among the various brands in the aftermarket gear space, Revolution Gear & Axle is one of, if the the most trusted name known for quality and reliability. In this article, we’ll dive into what makes Revolution a solid choice after decades in the business, with my personal choice being the 4.88s.
Table Of Contents
About Revolution Gears
Revolution Gear and Axle has built a strong reputation in the off-road and performance communities for producing precision-engineered gear sets. Known for their tight tolerances, premium heat-treated materials, and durability, they’ve become a go-to for enthusiasts and pros alike.
They offer a wide selection of gear ratios, axle shafts, and differential rebuild components, all made to withstand rugged conditions. Whether you’re rock crawling in Moab or exploring high alpine trails in BC, Revolution’s products are built for abuse.
Additionally, they offer solid support and warranty coverage, which gives peace of mind when investing in a job that’s both time- and labor-intensive.
Buying gears can be a confusing process. If you have ANY questions, you can call Revolution and someone will help you!
Why Choose 4.88s?
If you’re running larger tires (like 34s or 35s), a rooftop tent, sliders, bumpers, or a drawer system, your rig is working harder to move all that mass—especially on inclines. This is where 4.88 gears shine. The alternative, 4.56, are still a solid upgrade, but many who go that route often regret it. So if you’re planning on doing any kind of off-roading, hauling, or building a heavier truck – just go with the 4.88s. I’ll do a deeper dive on this topic in a separate post.
Top Benefits:
- More low-end torque for technical trail crawling
- Restored throttle response and drivability after upsizing tires
- Better performance in loaded or overlanding conditions
- Prepares your rig for even bigger tires (like 37s)
Features
The Revolution Gear and Axle 4.88 gear set is engineered specifically for the 5th Gen Toyota 4Runner platform, delivering enhanced performance for off-road enthusiasts and overlanders who demand more torque and durability.
Key Features:
- Optimized Gear Ratio: The 4.88 ratio provides increased low-end torque, improving acceleration, towing capacity, and technical off-road crawling ability—ideal for rigs with larger tires (33”+) and/or heavy payloads.
- Premium Materials: Crafted from 8620 steel and heat-treated to OEM specifications, ensuring exceptional strength and long-lasting durability under the toughest conditions.
- Precision Bearings: Equipped with high-quality Timken bearings included in the master install bearing kit, promoting smooth operation and precise gear alignment.
- Complete Gear Package: Contains front and rear ring and pinion gear sets, along with a master install bearing kit, all designed for professional installation.
- Manufactured in Korea: Produced under strict quality control standards, guaranteeing reliability and consistency.
- Enhanced Off-Road & Towing Performance: Perfect for heavy-duty overlanding, towing, and tackling challenging terrain where maximum torque and durability are essential.
Installation Overview
Installing gear sets like the Revolution 4.88s is far from a simple weekend bolt-on project—it’s a highly precise mechanical job that directly impacts your drivetrain’s performance, longevity, and noise levels.
The process involves carefully setting gear backlash, pinion depth, and bearing preload to exact manufacturer specifications. Even small deviations can cause premature wear, gear noise (like chatter or whining), or worse—catastrophic gear failure. Proper setup requires specialized tools such as dial indicators, torque wrenches, a hydraulic press, and bearing setup tools.
Unless you’re an experienced DIY mechanic who has performed differential gear installations before and owns this professional equipment, it’s crucial to entrust the job to a driveline or differential shop that specializes in gear installs. These shops have the expertise, precise measurement tools, and know-how to dial in your gears perfectly, ensuring smooth, quiet operation and durability.
Trying to rush this step or having it done by a general mechanic unfamiliar with gear setups often leads to headaches, wasted money, and a noisy or unreliable drivetrain.
Investing in a qualified shop to handle your gear installation is a key part of getting the full benefit from your upgrade—ultimately saving you time, money, and frustration down the road. That said, it’s not really the gears that are the expensive part of upgrading. In fact, I would call them relatively well priced for what you get (like that light bar most of us never really use). The disassembly and assembly of both differentials is a lot of book time and it’s a precise job. Something to keep in mind.
On a final note, I also installed a front locker with my gears. Check out my Eaton E-Locker review for more.
Performance Review
Off-Road:
Swapping to 4.88 gears completely transformed how the 4Runner handles technical trails. Instead of fighting to stay in the powerband, the throttle response now feels immediate and predictable—especially when navigating rocky switchbacks or loose hill climbs.
With the new gearing, the rig feels more confident crawling over ledges and through ruts, even when fully loaded with camping gear. The extra mechanical advantage takes pressure off the transmission, reducing the need to constantly feather the throttle or downshift.
Whether you’re creeping through a boulder garden or inching up a muddy incline, the 4Runner stays composed and controlled. It doesn’t just feel more capable—it actually performs like a different vehicle off-pavement.
On-Road:
Despite what people might think, I didn’t notice any annoying hums or gear whine at highway speeds. Yes, the RPMs are higher (~2500 RPM at 70mph on 35s), but it’s manageable. Just don’t expect hybrid-level MPGs—mine have been somewhat stable, but others have noted a small increase in fuel efficiency, some a decrease (but it’s tough to know exactly why). I’ve seen some Toyota owners report decent MPG improvements that could offset costs long term. Either way. Totally worth it for trail confidence and drivability.
Durability & Reliability
After extensive time on the trail—ranging from dusty backroads and high-speed gravel runs to technical rock crawling and snowy mountain passes—the Revolution Gear & Axle 4.88s have held up exceptionally well. There’s been no chatter, backlash, or excessive noise, even under tough conditions. Feedback from others running Revolution gears echoes this durability and reliability, reinforcing their reputation as a product built to last.
Revolution also stands behind its products with a solid warranty and responsive customer support, which proved helpful during the more complex installation and break-in period. Knowing you have that backing adds peace of mind for anyone upgrading their drivetrain.
Before deciding if these gears are the right fit for your build, here’s a balanced look at their main advantages and drawbacks…
Pros:
- Excellent build quality and precise fitment
- Noticeable performance gains in off-road scenarios
- improved overall drivability
- Durable and quiet operation when properly installed
- Trusted and respected brand within the off-road community
- Strong warranty and reliable customer support
Cons:
- Installation is challenging and not typically a DIY job
- Increased engine RPM on highways can result in lower/similar fuel economy (but again, a nuanced topic)
Final Thoughts
After putting the new gears to the test on multiple camping and off-road wheeling trips, these definitely stand out among my modifications. Tackling steep inclines, rocky terrain, and heavy loads during our weekend adventures confirmed the 4.88’s exceptional low-end torque and crawlability. Whether climbing technical sections or towing gear up rugged trails, the difference was noticeable — the truck felt more confident and responsive.
On the downside, the installation process was more involved than a simple bolt-on, and my highway fuel economy took a small hit. However, when you’re focused on building a rig designed for exploration and off-grid adventures, these trade-offs are a reasonable price to pay for enhanced capability and reliability.
If you’re running bigger tires (33” and above) or planning a heavy overland build, the 4.88 gears offer a clear performance advantage that’s hard to beat.
Robust, well-engineered, and delivering a real-world boost in drivability, these gears earn high marks for anyone serious about trail performance and heavy-duty use.
I upgraded mine with Nitros when I stepped up to 285/75’s and agree they were the best upgrade given the need of how we use our 4runner. I definitely have a gear hum up to 70mph (uncorrected spedo) but never really go above that simply to keep my rpm’s down. I’ve gotten used to it though… my wife, not so much!
Definitely one of the best mods that I’ve done so far, and surprisingly, there’s no hum with these Revolutions. That extra low-end torque is money.