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M/T - Synchronizing Ring Diagnosing Failures

88porsche03

Subject: Determining Synchronizing

Ring Damage
Model

All
Group

3
Part Identifier 3590
Number

8801
February 12, 1988
This bulletin will aid in diagnosing synchronizing ring failures. All of the examples shown are the result of improper operation such as "speed shifting" where the hand is faster than the foot or forcing gears.

The synchronizing rings are over-worked if the clutch pedal is not all the way depressed when shifting and the engine torque is transferred via the synchronizing rings to the intercept stops. This damages the synchronizing rings and causes cracks, breaks, heat spots and metal transfer between synchronizing rings and gear cones.

The described damages are not covered by warranty.
911 Carrera G50 Transmission 928S and 928 S4 from 1985



Broken stop for sliding sleeve



Metal transfer from synchronizing ring

911 Carrera G50 Transmission 928S and 928 S4 from 1985



Broken teeth



Broken teeth (1) and damaged stop (2)
4 Cylinder Cars



Metal transfer from synchronizing ring



Worn gear cone
4 Cylinder Cars



Damaged intercept stop (1) crack on intercept stop (2) rounded teeth (3)



Worn synchronizing ring and damaged teeth