6 V6-3.7L (2009)
Synchronizer Hub: All Technical Service Bulletins
M/T - Noise/Hard To Shift Into 3rd Or 4th Gear
Bulletin No: 05-002/10
Last Issued: 01/29/2010
Subject:
GEAR NOISE AND HARD SHIFTING INTO THIRD OR FOURTH GEAR
APPLICABLE MODEL(S)/VINS
2009-2010 Mazda6 with 6-speed M/T (G66M-R)
2010 Mazda3 with 6-speed M/T (G66M-R)
DESCRIPTION
Some customers may complain about a gear noise and/or hard shifting into third or fourth gear on the 6-speed M/T because the third or fourth gear
synchronizer ring may be worn excessively. One of the causes of synchronizer ring wear is driving the vehicle in neutral gear for fuel economy, called
Neutral driving." When acceleration is then needed, the driver must shift into a gear from neutral. In such a situation, it is easy to cause damage to the
synchronizer ring because of the difficulty to synchronize engine speed and gear speed for engagement. Third gear has been modified since lot
8**0311610; Lot number is as follows:
Customers having this concern should have their vehicle repaired using the following repair procedure.
REPAIR PROCEDURE
1. Verify customer concern.
2. Replace the 3rd and 4th synchronizer rings with modified parts. If the parts related to the 4th gear are damaged (such as gear and hub), replace with
new ones.
3. Verify repair.
EXPLANATION TO CUSTOMER
If the customer seems to drive with the vehicle in neutral gear (coasting along flat roads or downhill with the transmission in neutral), explain the
following to the customer.
Do NOT drive with the vehicle in neutral gear - it does not help fuel economy. Despite being in neutral gear, fuel keeps going to the engine while it is
running. Taking your foot off the accelerator pedal is much more helpful to fuel savings rather than driving in neutral gear because the Mazda engine
management system stops fuel to the engine when the throttle valve is closed. For instance:
Case A: The vehicle is moving with the transmission in neutral gear while taking your foot off the accelerator pedal => Fuel keeps going the the engine
to run it at idle speed, let's say, 750 rpm.
Case B: The vehicle is moving with the transmission in any gear while taking your foot off the accelerator pedal => Fuel is stopped from going to the
engine despite the engine speed indicated, let's say, 1500 rpm.
As you can see, Case B is much more beneficial than Case A. From other technical stand points, frequently driving in neutral gear may reduce the service
