While the Traxxas Revo 3.3 is a very capable racing platform on its own, Traxxas always strives to push their vehicles to a point above and beyond what it offers you when it’s pulled out of the box. If you spend a little time looking through some of the upgrades available for each vehicle, you will quickly recognize this. Along those lines, Traxxas saw a chance to further enhance the handling and performance of the Revo platform with their Center Differential and Rear Brake Kit.

These two new upgrades from Traxxas are designed specifically for the chassis and transmission housing included with the Revo 3.3. This being said, they’ll install onto the Revo 3.3 with minimal effort. However, they will also work with the Revo 2.5, as well. You’ll just need to modify the chassis and replace the rear half of the transmission housing.

This is an upgrade that has many racers excited and has even caused some racers I know to sell their non-Traxxas trucks so they can buy a Revo. After all, if you’re looking for an edge, there’s no doubt that a center differential and split braking will give it to you, provided it’s set up correctly for the conditions. Let’s spend a little time dissecting this latest upgrade path from Traxxas.

I’ll start off with a walkthrough and installation of the Traxxas Center Differential and Rear Brake Kit. It’s not a difficult install at all, but you will want to start with a clean work area and allow yourself plenty of time. Rushing through an installation will often cause you to make a few mistakes.

As with the Traxxas Revo 3.3 review, keep in mind that all of the pictures below will open to larger versions for a closer look. All you need to do is to click on them. Towards the end of the article you’ll find several pictures of my modified Revo 3.3 in action, as well as some video of it at the local track. Now, let’s head to the worktable!

In the event you’ve been living under a rock for the past few months, let me briefly give you explanation of what are debatably the most highly anticipated items for the Traxxas Revo. These items are the Traxxas Center Differential and Rear Brake Kits. These are two separate items, but are intended to be used together. The Center Differential Kit is Traxxas Part #5414, and the Rear Brake Kit is Traxxas Part #5417.

The Center Differential Kit allows you to split the power that’s sent to the front and rear of the truck. Unlike a standard Revo transmission, the center differential is similar to the differentials found at the front and rear of the Revo. Differential oil viscosity determines how much power the differential sends to the end of the truck that’s pulling the hardest. A standard transmission shaft is solid, and therefore sends its power to both ends of the vehicle equally.

Since the differential splits the vehicle into front and rear, the stock front brake alone will not be effective in helping to stop the rear wheels. This will introduce an under steer condition when braking as you enter a corner. So a split braking system had to be developed, hence the Traxxas Rear Brake Kit. This kit not only provides braking to the rear of the truck, but you also gain the ability to change the front to rear braking bias to enhance the truck’s ability to enter a corner sharply. The Traxxas Rear Brake Kit should really only be used to compliment the Center Differential. There is no point in installing the Rear Brake on a stock transmission. You won’t gain any real benefits, and the stock brake is plenty powerful on its own to stop a Revo with a stock transmission.

Much of the Traxxas Center Differential Kit should look familiar to anyone who has been running a Revo for a while. The differential cup and spider gears are the same parts used at the front and rear of the Revo. The output gears have been replaced with versions that have much longer output shafts however, and a plastic main gear replaces the steel ring gear found on the other two differentials.

The Traxxas Center Differential is sealed just as the stock Revo differentials are, using a combination of rubber gaskets and silicone x-rings. Inside the differential is much thicker oil, though, as the Traxxas Center Differential Kit comes with 100,000 weight differential oil inside the cup. The thicker viscosity oil is necessary due to the structure of the differentials internals, and the fact that the front and rear differentials are being driven by it. So this is why you see much thicker oil used than with other vehicles that utilize a center differential. Four screws keep the differential’s main gear secured firmly to the differential’s cup.

There are a few other items that arrive with the kit, and these may look familiar to anyone who has ever installed a Traxxas Forward-Only Conversion Kit onto their Revo. This is because the Traxxas Center Differential Kit also functions as a Forward-Only Conversion, eliminating the reversing components of the truck. You’ll find all of the items to cover up the OptiDrive openings, as well as a replacement primary gear.

Installing the Traxxas Center Differential Kit is easy and should feel very similar to installing a Traxxas Forward-Only Conversion Kit. First, remove the transmission from the truck and carefully open it up. Then, remove the c-shaped stainless steel clips on the primary gear. Once the clip is removed, you can slide out the pin that holds the primary gear in place.

Along with the primary gear, remove the main transmission shaft, as well as all of the reversing and OptiDrive components of the transmission. Most of these items will be in the front half of the transmission. The main shaft and black forward gear may end up on one side or the other depending upon how you pulled the transmission housing apart.

Now it’s time to install the actual components of the Center Differential Kit. Slide the new primary gear into place on the two speed shaft. Then secure it using the supplied screw pin. The Center differential should be slid into place afterwards. The direction of the differential should be obvious for the gears to properly mesh. However, to avoid any confusion, the main gear on the differential should be facing the rear of the transmission housing.

With the transmission internals addressed, it’s time to quickly take care of a few items on the outside of the transmission. First you’ll want to remove the OptiDrive sensor. Two screws are all that holds it on, and then it should pull right off. The shifting lever should be removed as well. Using a nut driver, unscrew the locknut that holds the braking adapter into place. Then lift the adapter up, and work the reversing spring lever off of the brake shaft.

Once the reversing lever is removed, replace the brake adapter. Keep in mind that it’s keyed and will only fit in a certain direction. If you’re having trouble getting it back on, ensure that you have it lined up correctly. Then rethread the nut onto the brake shaft to hold the adapter in place.

The opening left by the OptiDrive sensor should be covered by the plastic block-off plate provided in the kit. It installs in the same fashion as the sensor did, and is held in place by two screws. The blue silicone plug should be pressed into the hole left by the shaft for the transmission’s reversing fork. Once this is done, reassemble the transmission halves. Set it aside; as we’ll still need it separate from the vehicle for the installation of the Traxxas Rear Brake Kit.

Since the reversing components are removed, there’s no reason to still have the reversing servo installed. Simply remove it from the servo box on the left-hand side of the truck. The same can also be said for the OptiDrive unit. Remove it as well. You want to plug the throttle servo directly into the receiver.

Finally, since the receiver box lid has an opening specifically for the OptiDrive unit, you’ll need to use the supplied plate to close off the hole. Simply press the plate into place and reinstall the box’s lid onto the truck.

With the information regarding the Traxxas Center Differential out of the way, it’s time to cover the Traxxas Rear Brake Kit. This kit bears some resemblance to the components found on the Traxxas Jato. Installing the Rear Brake Kit is easy, as well, although trying to get everything properly set will tend to be a little more involved than just dropping a center differential in as I showed earlier.

The core components of the Traxxas Rear Brake Kit are the composite fiber brake disk and stainless steel pads. The kit also includes various screws and linkage items that will apply the brakes when they are called upon by the servo.

The first step is to install the brake disk adapter. The differential shaft that exits the rear of the transmission has a small hole in it about halfway between the transmission and its end. Slide the supplied pin for the disk adapter into the hole, and then slide the brake adapter down on top of it. The adapter should lock the pin into place once it’s slid all of the way down.

Next you’ll want to slide the brake pads into place on the disk adapter. They’ll fit snuggly into place. Then slide a stainless steel pad between the transmission housing and the first disk, another between the two disks, and the third on top of the second disk. Run the supplied screws down into place until they begin to get snug against the disk, and then back them off between a quarter to half a turn.

Next install the braking lever onto the rear of the transmission. The blue aluminum screws are used to hold it in place. Do not over tighten these screws, and check to make sure that the brake lever still pivots smoothly once they have been run in.

Now the time has come to reinstall the transmission back onto the Revo’s chassis. Once in place, go ahead and secure it to the chassis using the screws that pass through the skid plate and into the bottom of the transmission housing. Pass the linkage for the rear brake through the brake lever. The spring and adjustment knob should be towards the rear of the vehicle.

The next step is to connect the linkage to the servo horn found on the throttle servo. You’ll need to remove the horn from the servo to get it inserted into the linkage properly. Once you have reinstalled the horn, check the motion range of the braking linkage. It should not bind against the transmission at any point throughout the travel. It also should engage the brakes only when you move the throttle trigger forward. If you see the linkage rod binding, or engaging the brake when the carburetor is opened, you need to readjust the position at which the horn rests on the servo when the servo is at a neutral position.

As a final step for installing the Traxxas Rear Brake Kit, you need to trim the opening for the brake linkage in the lid for the servo box. Use a Dremel, or other cutting tool, and enlarge the opening in the box’s lid to accommodate both the front and rear braking linkage. (Editor's Note: Use extreme caution and all appropriate safety gear, such as safety glasses, with power tools. Keep hands and loose articles of clothing clear of cutting and drilling tools. Adult supervision required.) Once you’ve finished, trial fit the lid onto the box, ensuring you have proper clearance and that the linkage never contacts the box.

I figure it would be best to give you a quick rundown of what I have changed on the Revo 3.3 to compliment the Traxxas Center Differential and Rear Brake Kit installation. Since these Traxxas upgrades are targeted towards the racing crowd, I figured it would be much more appropriate to move my Revo 3.3 towards a configuration that would fall in line with it being raced. This would help me maximize the potential of the Traxxas Center Differential and Rear Brake options.

Since I also planned to use the truck in some upcoming races, this would allow me to go ahead and start dialing in the truck like I wanted it. While the Revo performed well in stock trim, changing out a few items would definitely allow me to push the truck a little harder on the track.

I started out knowing that I would be changing the truck’s tires. Track grip would be very important when testing these new options. To accomplish this, I fell back to my overall favorite tire option, a set of Panther Pythons. The Pythons work very well at my local track, and exhibit very little wear on the hard track surface. The tires were mounted on a set of cut 40 series Pro-Line Wabash wheels. To mount the wheel to the truck, I used the RD Racing axle carriers and 23mm hex adapters. While there are many 23mm conversions one can take, I feel the RD Racing setup best matches the attention to detail, fit, and finish that Traxxas provides with the Revo initially.

In the process of making this swap, I also changed a few other items. The stock pushrods were replaced with the Traxxas aluminum ones (Part #5318X). There’s absolutely nothing wrong with using the stock pieces, but I had grown accustomed to the look of the red anodized aluminum on my other Revo. So I carried it over to the new Revo 3.3, as well. Besides, it would also shed a little weight off of the truck. The same can be said for the Traxxas Tubes (Part #5338R), as I swapped the stock toe and steering links for a full set of them. I’ve been running the Tubes on my other Revo since they were first released, and the tubular design Traxxas used has shown itself to be incredibly tough. Despite some mishaps on the track, the Tubes have always come away in perfect shape. I have yet to have one single issue with them at all. I swear by them now!

There were a few other minor changes I made, as well. Knowing that the track would have many more people present during my next test session, I opted to change the radio equipment. I swapped in a Spektrum receiver, while planning on using my Spektrum radio, as it would allow me to not have to worry with the frequency board, or the fact someone may turn on a radio in the pit area while I’m on the track. I also removed the EZ-Start, and converted the TRX 3.3 over for use with my RD Racing starter box. While eventually I will further tweak my truck, I felt that these changes would at least get me closer to a truck that would model one prepped for the track.

During the course of my testing I also allowed myself to make changes to the truck involving areas such as the differential oil, and suspension settings. While I’m always playing with settings, and it may vary slightly from track to track, or even day to day, you’ll find a copy of my setup sheet at the end of this article. This may help you establish a baseline to start from for your own truck.

With my changes made, I headed back out to Monkey Bottom Raceway, where I had performed the testing for the first part of the Revo 3.3 review. The day was warm and sunny but not oppressively hot and humid as weather in North Carolina can sometimes be. In other words, it was a perfect day to be at the track!

As I had guessed, there were quite a few people already at the track when I arrived. Many of them knew what I had with me, and there were a few people who were very curious. The scoring system was set up for some testing before the next club race. This came in handy a little later after I made some changes, when I compared some of my times during the practice session with a known general average lap time.

I hit the track soon after arriving, and the first thing I noticed was the fact that the Revo 3.3 wanted to shoot away like a rocket. While the stock tires performed much better than I had expected, previously, the new rubber really let me put the power of the TRX 3.3 to the ground. I started around the track and took it easy for the first lap to allow the motor to warm up fully before I started to put the hammer down.

After I made a lap, it was time to get to business. Once I rounded the last corner, I nailed the throttle and the truck shot down the straightaway, promptly responding by kicking into second gear. As it flew down the straightaway it left a plume of dust in its wake. I backed of the throttle for the first turn, cut the wheel and applied a little brake to kick the rear of the truck out. Then I stabbed the throttle again, and cleared the double effortlessly. I then applied the same throttle technique to the triple soon afterwards, although I still used my conservative double-single approach on the triple.

I ran the track completely and quickly burned through a tank of fuel. At that point I retrieved the truck, and headed to my pit table to make a few changes to suit the conditions a little better. I noticed the truck seemed a little loose in the rear when exiting a corner. Then as the truck straightened up, or headed down the straightaway, the center differential seemed to unload which sent a little more power towards the front than I wanted to see.

To start out with, I had swapped my front differential oil out for 30k weight and the rear out for 20k weight. I wasn’t sure if the Revo’s center diff would work better with the oils more similar or different when it comes to their viscosity. I made a mix in the center differential that would be around 200k. The stock oil, if you’ll remember, is 100k. These viscosity numbers may seem high to some people. However, keep in mind that the Revo’s center differential uses a four gear setup and, therefore, needs a much higher viscosity differential oil that some may be used to.

While I had the truck apart, I also made some changes to the suspension. I swapped out the stock springs and moved up one step all the way around. This gave me orange dot springs in the front, and gold dot springs in the rear. I also swapped out the stock shock oil for some 45 weight oil. The truck’s suspension had been compressing a little more than I was typically used to. While that helped enhance traction with the stock Talon tires, the race rubber I now had on the Revo 3.3 was able to grip without the need for a lot of body roll and suspension compression. These changes would keep the truck more level while cornering and provide a little more responsiveness overall.

I then buttoned the truck up and hit the track once again. These changes set the Revo 3.3 up with a very comfortable balance. The center differential pulled the truck around the track plenty hard enough and allowed me to exit the turns under more power than I was typically used to. This provided a much more controllable punch out of the corner, and it certainly showed when I squeezed the trigger.

The ability to tailor the front to rear brake bias helped tremendously as well. I ended up setting the truck’s rear brakes to give me around 70% of the overall braking force, while the front carried the other 30%. This made the rear end of the truck pivot well entering a corner after the front wheels were turned. Then I started to straighten the wheels and stab the throttle. The front differential took over and carried the truck out of the turn.

The Revo, as a whole, felt much more responsive and sure-footed with the center differential and rear brake kit installed. It felt like an entirely different truck, in regards to how well it ran through the corners. The increase in cornering ability also allowed me to hit higher speeds throughout the track, with some of these having a very positive impact on upcoming jumps. The doubles and tabletops were much easier to hit consistently, and, even though I normally take the conservative route on the big triple for consistency, I found I could clear it if I hit the foregoing corner just right.

While the proper setup will vary from track to track and driver to driver, it is very clear to me that the Traxxas Center Differential and Rear Brake kit are a huge enhancement to the truck when properly setup. After running and tweaking on the truck throughout the afternoon, I saw average lap times that were nearly 1.5 seconds faster than my normal average lap times. The new Traxxas upgrades on the Revo 3.3 allowed me to drive it much harder than it could otherwise, and my lap time improvement showed this improvement dramatically. Not once did I see any signs of brake fade with either set of brakes. Obviously, I know how rock solid the front brakes already are. But considering the fact that the majority of my braking was handled by the rear brake, fade should have shown up if it was going to be an issue.

I’ll still be tweaking on my setup in the coming weeks, but one thing won’t change. That’s the fact I’m sold on the positive benefits that this upgrade has made to my Revo 3.3. As if the Revo 3.3 by itself wasn’t enough, Traxxas raised the bar even higher by offering their center differential and rear brake option!

The Revo 3.3 already has the capability to handle any track that’s thrown its way. However, with the newly released Traxxas Center Differential and Rear Brake Kit the truck can run a track with more precision than ever before. The Center Differential allows you to lay the power down more smoothly exiting turns, while the Rear Brake Kit allows for a sharper entry to set you up for the eventual exit from the corner.

My Revo 3.3 drives like an entirely different truck now, and I’m still getting used to running it through the corners. I still have plenty of practicing to accomplish with the new upgrades, and I want to experiment even further with the suspension and differential oils. However the truck is very close to my ideal setting, and, with these changes on a Revo 3.3, it’s racing around the track much faster now than I ever thought possible. Without a doubt, these upgrades make the Traxxas Revo 3.3 the ultimate trackside monster truck!