M/T - Knocking or Tapping Gear Noise: Overview
90chevy16Number: 89-293-7B
Section: 7B
Date: January 1990
Corp. Bulletin No.: 977204
Subject: KNOCKING OR TAPPING NOISE IN ALL GEAR RANGES AND NEUTRAL WITH CLUTCH PEDAL OUT
Model and Year: 1989 A, J, L CARS WITH HM-282/5TM40 MANUAL TRANSMISSION
THIS BULLETIN CANCELS AND SUPERSEDES DEALER SERVICE BULLETIN NO. 89-267-7B, DATED SEPTEMBER 1989. ADDITIONAL INFORMATION UNDER BULLETIN COVERS PROPER DIAGNOSIS. A CHART ADDED FOR MODEL BREAKPOINT AND SERVICE PROCEDURE (1ST PARAGRAPH) HAS BEEN ADDED. ALL COPIES OF 89-267-7B SHOULD BE DISCARDED.
This bulletin covers some HM-282/HYDRA-MATIC 5TM40 Transaxles built between approximately November 1, 1988, and April 7, 1989, which may exhibit a knocking or tapping noise in all gears and neutral with the clutch pedal out. This condition is termed Gear Noise.
PROPER DIAGNOSIS IS IMPORTANT: Do not confuse this Gear Noise with Clutch Rattle or Neutral Gear Rattle. A knocking or tapping noise which is only heard in neutral with the clutch pedal out is clutch rattle or neutral gear rattle. Reference Dealer Service Bulletin No. 88-351-7B.
DATE OF PRODUCTION CHANGE:
Figure 1:
A vehicle equipped with a HM-282/HYDRA-MATIC 5TM40 built between approximately November 1, 1988, and April 7, 1989, may exhibit the gear noise condition described above. Refer to the chart below for specific model breakpoint information: