Cruise Control - Slight Surge Above 50 MPH

Bulletin No. T 87-127
File in Group 9
Number 38
Corp. Ref. No. 718205
Date July '87
SUBJECT: CRUISE CONTROL SURGE

MODELS AFFECTED: 1985-1987 DE VILLES AND FLEETWOODS

Some 1985-1987 De Villes and Fleetwoods may experience a condition of slight cruise control surge. This condition usually occurs above 50 mph (80 km/h) and is more pronounced after reaching normal operating temperatures. This condition may be caused by an erratic Vehicle Speed Sensor (VSS) input, which cannot be detected while in parameters. This erratic input may be caused by looseness in the VSS drive and driven gear.

To repair this condition, proceed as follows:

1. Remove VSS and governor assembly.

2. Inspect VSS drive and driven gears for damaged or broken teeth and replace as necessary and proceed to Step 3.

3. Obtain .005" (1.270 mm) brass shim stock.

4. Using the .005" brass shim stock, cut a piece 5/16" x 1-9/16"(8 x 40 mm).

5. Remove governor gear (pull off).

Figure 1 - Drive Gear Shim:

6. Wrap this shim around the governor shaft and install drive gear over the shim ensuring a press fit and eliminating any looseness (see Figure 1).
7. Shim stock should not cover bearing contact surface, trim flush with the top of the gear if necessary.

8. Remove VSS gear (pull off).

Figure 2 - Driven Gear Shim:

9. Using the .005" brass shim stock, cut a piece 15/16" x 1/4" (14 x 24 mm) and wrap this shim around the VSS shaft and install gear onto shaft, ensuring all looseness is eliminated.
10. Trim excess shim stock if necessary.

For warranty purposes, use Labor Operation T6227 at 1.0 hours.