Centering the Shift Servo
The shift servo has been correctly centered from the
factory. The following instructions have been include for
your reference.
I.
Remove the 3x10mm button head screw from the
shift servo horn, and then remove the spring, servo
horn, and the notched sleeve from the servo (1X).
II. Turn on the transmitter and the ON/
OFF switch on the model. Make sure
that the red forward/reverse switch on
the transmitter is positioned in the UP
(reverse) position (2X). Install the sleeve
back onto the splined output shaft of
the servo with the notch in the “12
o’clock” position (3X), and
then turn the radio system
and truck off.
III. Set the servo horn back
on top of the adapter as
shown (4X), and then place
the spring onto the servo
horn. Make sure to put the bottom end of the wire
into the single hole (not the slot) located in the servo
horn (5X).
IV. Secure the assembly to the servo with the same
3x10mm button head screw (6X).
www.TRAXXAS.com
Traxxas, 1100 Klein Road, Plano, TX 75074, Phone: 972-265-8000, Fax: 972-265-8011, e-mail: support@Traxxas.com
3. Shift to forward gear on the transmitter. Again, roll the truck a few inches to
fully engage the shift mechanism in the transmission.
4. Check the “pre-load” on the shift spring. It should be about the same as it was
in second gear (but in the other direction).
5. If the spring pre-load does not feel similar in forward and reverse gear, remove
the servo horn and reinstall. Start with step I. of
Centering the Shift Servo
, and
make the following adjustment:
a. If the spring was tight in reverse gear, but loose in forward gear, install the
notched servo saver sleeve one tooth clockwise from the original position
(see step II. of
Centering the Shift Servo
).
b. If the spring was tight in forward gear, but loose in reverse gear, install the
notched servo saver sleeve one position counter-clockwise from the original
position (see step II. of
Centering the Shift Servo
).
Forward/Reverse Shifting Tips
• This kit does not include the OptiDrive module. The truck must come to a
complete stop before shifting.
• After the truck has come to a complete stop, press the red thumb switch up to
actuate Reverse, or press down to actuate Forward.
• After shifting, allow the truck to roll slightly to ensure positive engagement of the
transmission. Once the truck lurches forward or back, it is then ok to apply throttle.
Caution: Do not switch gears at high speeds. This can cause serious damage to
the transmission gears.
OptiDrive System (optional)
The Traxxas OptiDrive electronic shift module uses advanced microprocessor
control to sense vehicle speed and optimize forward and reverse shifting. OptiDrive
also includes low battery voltage protection. These parts are the needed for
installing the OptiDrive system into the 4908 T-Maxx:
• #5398 - OptiDrive shift module
• #5397 - OptiDrive sensor assembly
*
2743
3x4 GS
4967
4967
5396X
*
5390
5393
5386
5393
5393
1985
5x8x0.5 TW
5390
6x8x0.5 TW
3982
5390
3982
6x8x0.5 TW
3982
6x8x0.5 TW
5121
6X10 NRB
(Text on bearing
towards shaft.)
5121
6X10 NRB
(Text on bearing
towards shaft.)
5116
5x11 BB
3215
2.5x6 CS
5397
5365
5365
5181
5181
5395
5395
5366
5352
5351
5351
2554
3x6 CS
3958 58T Opt.
3956 54T
3957 56T Opt.
5352X
5352X
5352X
5395
5389X
5164
4966X
4927X
4927X
M4/18.5
5117
6x12 BB
5117
6x12 BB
5117
6x12 BB
5116
5x11 BB
5352X
5352X
4147
5.0 NL
5119
10X15 BB
5393
Primary shaft
5369
Output shaft
Correct orientation on shaft
Shift Servo Assembly
5116
5x11 BB
2552
3x12 CCS
4978
3x21 Shoulder BCS
3982
6x8x0.5 TW
3982
6x8x0.5 TW
4927X
M4/14.5
4927X
5181
5116
5x11 BB
5366
5352X
5352X
(5.0 NL 4147)
5183
(includes bearing)
5183
5116
5x11 BB
5116
5x11 BB
5385
M3/13.75
(screw pin)
5384 (wide)
5385 Opt. (standard)
5383 Opt. (close)
5384 (wide)
5385 Opt. (standard)
5383 Opt. (close)
*Apply a light coating of automotive wheel bearing grease to these gears.
5157
5394X
4995X
3988X
4995X
3988X
4995X
3988X
2577
3X10 BCS
4995X
4995X
4995X
2576
3X8 BCS
4995X
2576
3X8 BCS
4995X
2575
3X6 BCS
4995X
2575
3X6 BCS
4995X
2065
FRONT
If you have questions or need technical assistance, call Traxxas at
1-888-TRAXXAS
(1-888-872-9927) (U.S. residents only)
1X
4X
5X
6X
2X
3X
Completed Installation
080812_KC1154_4908_FwdRev.indd 2
8/12/08 5:01:42 PM
