M/T - Reverse Gear Noise Prevention Mechanism
90mitsubishi01SUBJECT:
MODIFIED REVERSE GEAR MECHANISM
IN F5M/W5M (KM200) SERIES TRANSAXLES
NO. TSB-90-22-001
DATE January, 1990
MODEL Galant, Mirage, Eclipse, Sigma V6
PURPOSE
Some Galant, Mirage, Eclipse and Sigma vehicles equipped with manual transaxles manufactured in January 1989 have a noise prevention mechanism added to the reverse gear shifter assembly. Vehicles produced since March 21, 1989 have the before mentioned assembly in addition to a wave spring on the outer side of the reverse brake ring. This bulletin describes these mechanisms and their operation. Should you need to repair a vehicle with this modification, use the parts list and tables attached.
Figure 1:
TRANSMISSION IDENTIFICATION
Refer to figure 1 for the location of the transmission identification number.
Transmissions built between # HC6354 to # HG0585 have the noise prevention mechanism.
Transmissions built after # HM4393 have the noise prevention mechanism and the noise reducing wave spring.
Figure 2:
DETAILS OF MODIFICATION
F5M/W5M (KM200) series transaxles built between # HC6354 and # HG0585 have an added mechanism to stop input shaft rotation temporarily while shifting into reverse gear (Figure 2). This reduces gear "clash" and improves shift quality.
When shifting into reverse, the 5-R shift rail moves away from the engine. On the modified model the 5th speed shift fork carries the 5th speed synchronizer sleeve back, forcing the synchronizer keys against the reverse brake ring (similar to a synchronizer ring in conventional use). The reverse brake ring is forced against a stationary reverse brake cone (attached to rear cover), momentarily stopping the input shaft from rotation. As the 5th speed gear sleeve continues its motion toward the rear cover, it relaxes its pressure on the keys, which releases pressure against the brake ring. The input shaft can now rotate while in reverse gear.
This modification involves:
Changes to the following existing parts:
Rear Cover Synchronizer Sleeve Synchronizer Keys Shaft Lock Nut Addition of the following parts:
Reverse Brake Cone Machine Screws Reverse Brake Ring Dowel Pin Elimination of the following part:
Stop Plate
Figure 3:
ADDITIONAL MODIFICATION
Beginning with Transmission # HM4393 and up, a wave spring has been added to the before mentioned modifications. This ring is fitted on the outer side of the reverse brake ring to prevent noise at idle.
PARTS INFORMATION