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T-MAXX 2.5R
Adjusting the Two-Speed Transmission
T-Maxx 2.5R comes equipped with an adjustable two-speed transmission.
When the shift point on the transmission is adjusted correctly, it will
maximize acceleration and improve drivability. Use a 2mm hex wrench
to adjust the shift point. To make the adjustment, the engine must be off
(not running).
1.
Shift the transmission into forward gear
(shift button down).
2.
Remove the rubber access plug from the
top of the transmission housing.
3.
While looking through the
opening, rotate the spur gear to
align the cutout (notch) on the internal
2-speed clutch drum with the opening.
4.
Hold the spur gear and slowly roll the
truck forward until the hex on the black
adjustment set screw becomes visible in
the opening.
Note:
the truck will only roll
forward (not backwards) when the spur
gear is held stationary.
5.
Insert the 2.0mm hex wrench
through the clutch drum and into
the adjustment screw.
6.
Turn the adjustment screw 1/8 turn
counter clockwise to lower the shift
point (shifts sooner). Be careful not to
loosen the adjustment screw too much
or you may cause the screw and spring
to fall out (requiring major disassembly
and repair). Turn the adjustment screw
clockwise for later shifts.
7.
Reinstall the rubber access plug to prevent dirt from entering the
transmission. Do not put oil or other lubricants into the transmission
through the two-speed adjustment access.
8.
Check performance by running a test lap after each adjustment. On a
small race track with many tight turns, try setting the shift point later so
that the truck only shifts into second gear on the main straightaway.
This will prevent an unexpected shift in the middle of a turn. On larger
tracks it may be necessary to allow earlier shifts for increased speed.
Adjusting the Spur Gear/Clutch Bell Gear Mesh
The ideal spur gear/clutch bell gear mesh
for T-Maxx 2.5R is 0.1mm. To set the gear
mesh, place a strip of standard letter/A4 size
copy or printer paper (about 0.1mm thick)
between the mating teeth. Loosen the four
engine mount screws from the bottom side
of the chassis (see image) and slide the
engine mount up to push the clutch bell gear
against the spur gear so the paper is not too
tight to pull out or too loose that it will fall out.
Tighten the engine mount screws securely.
When the paper is removed, you should feel
only the slightest amount of play between the
gears (almost none) and there should be no
binding or friction.
Changing the Spur Gear
1.
Remove the four cap head screws that secure
the engine to the engine mount.
2.
Remove the button head screw that secures the
pipe hanger to the rear body mount (see inset).
3.
Carefully remove the engine and exhaust system
from the spur gear area to allow enough room to
remove the spur gear.
4.
Remove the three screws on the slipper clutch assembly using a 2.5mm
hex wrench. Slide the spur gear off of the slipper shaft. If the spur gear
is too tight on the shaft, gently pry on the back of the gear with a flat
screw driver to loosen it.
Repeat the above steps in reverse order to install the new spur gear
Adjusting the Gear Ratio
The gear ratio on T-Maxx 2.5R can be adjusted for different conditions
that may require either increased acceleration or increased top speed.
Adjusting the gear ratio is accomplished by changing the clutch bell on
the engine and/or the spur gear (slipper clutch gear) on the transmission.
From the factory, T-Maxx 2.5R is equipped with a 20-tooth clutch bell
and a 54-tooth spur gear. This combination will provide a good balance
of acceleration and top speed. Optional spur gears and clutch bell gears
are listed on your parts list. Refer to the chart on page 39 for possible
gearing combinations.
Shift
Sooner
Two Speed Adjustment
note: If the truck will not roll
forward while the spur gear
is held, the transmission
may still be in reverse gear.
Tuning Adjustments
Counter-
Clockwise
Summary of Contents for 4902
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