Traxxas 4902, Owner'S Manual

T-MAXX 2.5R

•

15

Servo Reversing Switches

The servo reversing switches are located on the front of the transmitter,
next to the on/off switch. Moving a switch reverses the direction of the
corresponding servo. Each switch corresponds to a channel, as shown
below. For example, if you turn the steering wheel to the right and your
front wheels turn left, you would move the channel 1 switch to correct
the servo direction. It may be necessary to adjust the corresponding trim
control after
moving a switch

.

The default
position for the
servo reversing
switches is shown.

Programming the OptiDrive

™

ESM

The OptiDrive ESM electronically monitors
vehicle speed and controls forward and reverse
shifting. Controlling the shift action electronically
rather than by mechanical systems reduces the
number of components in the transmission. The
transmission weighs less, there is lower
rotational mass for quicker acceleration, and
constant drive engagement for smooth power delivery. 

The OptiDrive module prevents the transmission from changing
directions while the truck is in motion. The truck must be completely
stopped to change directions, regardless of the position of the shift
selector switch on the transmitter. The OptiDrive module is preset at the
factory. If the transmitter throttle trim adjustment is changed, then the
OptiDrive module will need to be re-programmed.

1.

The engine must be shut off. The radio system must be on (receiver

and transmitter).

2.

Set the TQ-3 Transmitter to its factory default shift settings:

Set the THROTTLE NEUTRAL switch to the 50/50 setting.
Set the THROTTLE TRIM to the center “0” setting, then adjust the

throttle linkage until the carburetor closes. 

Set the CHANNEL 2 SERVO REVERSING SWITCH to the right position.
Set the CHANNEL 3 SERVO REVERSING SWITCH to the right position.
DO NOT change the position of any of the servo reversing switches

after programming the OptiDrive. If settings were changed after
programming the OptiDrive, it will have to be reprogrammed.

3.

With the throttle at neutral, press and hold the

SET button until the Function LED flashes green
twice and then release the button immediately.
You are now in programming mode.

4.

Pull the transmitter throttle

trigger to the full throttle
position. Hold it there until the
Function LED flashes green
three times. 

Note:

The throttle

servo will not move during programming even though it is connected
to the controller.

5.

Release the transmitter throttle

trigger allowing it to return to
neutral. The Function LED will
turn solid green, indicating that
the shifting servo is OK to shift
and the programming has been completed. The controller is now
programmed and ready to go!

If the transmitter throttle settings are changed, it will be necessary 

to complete the programming sequence again.

If the SET button is released before the Function LED flashes 

green twice in step 3, the OptiDrive will return to the normal
operation mode.

If you experience any problems during programming, turn the

receiver off, then on again, and repeat the programming steps.

For instructions on how to use the OptiDrive with aftermarket radio
systems, or to access advanced programming options, visit our website,
www.Traxxas.com.

CH.3

CH.2

CH.1

Channel

Servo

1

Steering

2

Throttle and braking

3

Shifting

The Traxxas TQ-3 Radio System

Large adjustments to the
throttle trim and/or throttle
linkage may require re-setting
the OptiDrive to maintain
proper shifting action. 

TQ-3 Channel to Servo Chart

For transmission durability, 
the OptiDrive ESM  limits the
model’s reverse speed to about
70% of full throttle. If settings
are changed, and you notice a
decrease in forward top speed,
you could have the OptiDrive
system reversed. Return the
TQ-3 servo-reversing switches
for channels two and three
back to their default settings
and re-program the OptiDrive
Module. For programming with
aftermarket radio systems,
please see our website.

•

Green

“

Function

”

Shift allowed

•

Red flashing

“

Function

”

Low battery, see pg. 12

•

Red

“

Sensor

”

a) Sensor, throttle or shift   

circuit is broken. Possible

disconnected or broken sensor,
throttle or shift wires. Possible
damaged sensor. 
b) Receiver has lost signal from the
transmitter, the OptiDrive has
entered fail-safe (throttle and shift
servos become unresponsive). 

•

Blue flashing 

“

Sensor

“

Normal operation as
vehicle moves. Indicates

signal pulse from sensor. Depending
on the rotor position, solid blue or off
when vehicle is at rest. 

OptiDrive Operation