Factory Service Bulletin Header

GROUP: Automatic Transmission
SUBGROUP: Adjustment
DATE: 3-31-67

SUBJECT: Thumping Noise

MODELS: All Models Equipped With Borg-Warner 35 Transmission

Some cases of a thumping noise from the transmission have been reported when shifting into ‘D’ or ‘D1’. If you should encounter this, the following action is recommended:

  1. Be sure that engine idling speed is correct and that the throttle is not sticking.
  2. Check and adjust if necessary, downshift cable using a pressure gauge and tachometer. See WSM 139, Part 1, pages 8, 9 and 10.
  3. Remove transmission pan and valve block. Be sure that the following valves are free to operate and are not sticking:
    1. throttle valve
    2. primary regulator valve
    3. modulator valve
  4. Fit replacement 1st/2nd shift valve spring, part number 5039919.
  5. Re-fit valve block and pan. Re-fill with oil and road test as per WSM 139, Part 3, page 4.

T.H. Bullard
Manager – Service & Parts

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