The T-Maxx comes equipped with a two-speed transmission. When the shift point on this transmission is adjusted correctly, it will maximize acceleration and improve driveability.
Note: It is important that your engine is properly tuned and has reached full operating temperature before making shift point adjustments. Stop the engine before making adjustments.
- Stop the engine.
- Remove the larger rubber plug from the transmission housing.
- Look into the access hole in the transmission housing and rotate the spur gear until the access hole in the aluminum drum is visible.
- Once the access hole is visible, hold the spur gear and use your finger to turn the primary gear shaft counter clockwise which extends from the transmission housing (see photo). Note that you will see two set screws through the access hole. As you turn the primary gear shaft counterclockwise, the first set screw holds the two-speed mechanism to the shaft. Do not loosen this screw. The second set screw is the adjustment screw.
- Insert a 2.0 Allen wrench through the clutch drum and into the adjustment set screw (see diagram).
- Turn the adjustment screw 1/8 turn clockwise to raise the shift point (later shifts). Be careful not to overtighten the adjustment screw or you may damage the tension spring. Do not make constant adjustments or you will loosen the locking device.
- Turn the adjustment screw 1/8 turn counterclockwise to lower the shift point (earlier shifts). 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).
- Use 1/8 turn increments to find the approximate, desired shift point.
- Check performance by running a test lap after each adjustment.
- Use 1/8-1/16 turn increments to fine tune the shift point.
Note: The transmission may not shift if the adjustment screw is turned too far in (locked in first gear), or too far out (locked in second gear). If the truck has quick acceleration and does not appear to shift, the transmission is never reaching the shifting point. The shift point needs to be lowered by turning the adjustment screw counterclockwise. If the truck has poor acceleration but very high top speed, the transmission is shifting into second gear almost instantly. The shift point needs to be raised by turning the adjustment screw clockwise.