Note 1:
The center differential for the Traxxas Revo works
as a forward-only system, and is a direct replacement for
the Revo Forward-Only Kit (#5394X). For transmissions that
already have the Revo Forward-Only Kit installed, the shaft
and gear will be the only components removed from the
transmission. Replace the forward-only output shaft and
gear assembly with the center differential shaft and gear
assembly using the instructions below as a reference.
Note 2:
The long rear output shaft of the assembled center differential is
designed to fit the 30mm longer Revo 3.3 chassis. You may experience a slight
amount of interference with the rear output yoke when used with the standard
chassis. Material can be removed to remedy this, or the rear output shaft can be
replaced with a shorter shaft (#5416).
Removing the transmission
• Remove the brake linkage from the
brake arm by loosening the 3x12BCS
(button head cap screw)(see image A).
Disconnect the reverse linkage from the
reverse shift spring.
• Raise the cover on the right radio
box and remove the blue sensor
plug from the OptiDrive
™
module.
• Disconnect the transmission skid
plate from the bottom of the
chassis by removing the four
4x12BCS (image B).
• Remove the two 4x15mm screw pins (image B) that secure the front and
rear transmission yokes to the transmission output shaft. Remove both of
the transmission yokes from the output shaft, leaving the driveshafts
connected to the differentials. Lift the transmission out of the chassis.
Replacing the forward/reverse gears
with the forward only components
• Remove the six 3x12CCS
(countersunk cap screws) from the
transmission case, and carefully
separate the two gearbox halves
(image C).
• Remove the OptiDrive sensor from the gearbox
half and replace the sensor with the included
cover (image D). Use the same two 2.5x6CS
(cap screws).
• Remove the 3.0NL (nylon locknut) and the
brake lever from the brake cam to access the
shift fork spring. Remove the shift fork spring
from the brake cam and reinstall the brake lever
and 3.0NL back onto the brake cam. Note: The
shift spring and sensor will not be reused.
• Slide the shift fork with the drive dog carrier out
of the gearbox half, and plug the shift fork hole
with the included blue plug (image E).
(Note: The black shift shaft seal is glued to the
gearbox half from the factory. The plug can
be inserted into the gearbox with or without
the seal installed.) Remove the reverse idler
gear and the plastic gear support. Remove
the forward and reverse output gears,
output shaft and drive dog carrier along
with all four Teflon® washers located on the
output shaft. Remove the forward and reverse
primary gears (#5396) from the primary shaft,
and replace them with the forward-only primary gear. Secure the gear
with the screw pin (see pic F1 for correct orientation). Note: Newer
transmissions use a solid pin with a retaining ring to secure the primary
gear. Use a small flat bladed screwdriver to pop
the retaining ring off of the primary gear, and
then push the pin out of the gear for removal.
• Slide one Teflon washer over the rear
output shaft, and then install the center
differential assembly into the rear
gearbox half, and carefully join
the two gearbox halves together
(see images F1 and F2 for
orientation). Remember to insert
the brake disc between the brake
calipers before joining the two
gearbox halves. The output shaft
(exiting the front) must go through the center of the brake disc (located
between the brake calipers). Fasten the halves together with six 3x12CCS.
Removing the electronics from the chassis
• Unhook the air filter from the electronics box,
and remove the cover to access the shift servo.
Remove the shift servo from the radio box
(see image G) and unplug the servo from the
OptiDrive module. Set the servo aside, it will
not be reused. Reinstall the cover on the
electronics box, and place the air filter back
into the retainer.
• Unplug the throttle servo from the OptiDrive
module. Unplug the OptiDrive module from
channels 2 and 3 on the receiver (2-plugs = 1-
gray, 1-green) (see image H). Plug the throttle
servo into the CH2 port on the receiver.
• Reinstall the cover onto the right side radio box
and snap the small plastic cover (included) into
the hole where the OptiDrive module was
located (see image I).
Reinstall the transmission
• Set the transmission back onto the chassis and
slide the front and rear output yokes back onto
the output shafts of the tranny. The torque pins
on the front output yoke should key into the
slots stamped into the disc. Secure the yokes
with the two 4x15mm screw pins (see image J).
• Secure the transmission and the transmission
skid plate to the chassis with the four 4x12BCS.
• Reconnect the brake linkage to the brake arm
and secure it with the 3x12BCS. This completes
the procedure (see image K).
Driving and set-up tips
Form 5414INST Rev 060329
Center Differential Instructions (Forward-Only)
Covers Parts #5414, 5414X
4x12mm
4x15mm
4x15mm
4x12mm
3x12BCS
Components removed from
the transmission
Shift
Servo
Plastic
Cover
Blue Plug
1
2
3
4
5
6
A
B
Sensor
Cover
3.0NL
Brake
Lever
Brake
Cam
C
D
E
Assembled transmission
G
H
I
J
K
F1
w w w . T R A X X A S . c o m
Traxxas, 1100 Klein Road, Plano, TX 75074, Phone: 972-265-8000, Fax: 972-265-8011, e-mail: [email protected]
• The center differential allows the power
from the engine to be transferred to the
front and rear differentials independently
from one another. When the rear wheels
are under more load than the front
wheels, more power will be transmitted to
the front wheels. This is very beneficial on
rough terrain and makes hard acceleration
from low speeds easier to control by
keeping the nose down.
• The center differential is assembled with
100K wt. differential lube from the factory.
This viscosity will be a good base point for
most conditions. Thinner fluid will transfer
power easier than thicker fluid. Try thinner
fluid on extremely rough and slick
surfaces, and thicker fluid on very smooth
and high-bite surfaces.
• Using the center differential will also affect
braking performance. Since there is not a
solid shaft connecting the front and rear
differentials, the brake system located on
the front of the transmission housing will
only be effective for the front wheels. This
may cause a slight push while entering a
corner. Installing the Revo Rear Brake Kit
(#5417) will restore rear braking power,
and the ability to adjust front and rear
brake bias. This kit is recommended for
maximum performance.
F2
