Fleetwood FWD V8-252 4.1L (1986)
Governor: All Technical Service Bulletins
A/T - THM 440-T4 Second Gear Starts On Take-Off
Bulletin No. T
87-97
File in Group
7
Number
159
Corp. Ref. No.
717103
Date
April '87
SUBJECT:
THM 440-T4 SECOND GEAR STARTS ON TAKE-OFF
MODELS AFFECTED: 1985-1987 DE VILLES AND FLEETWOODS 1986-1987 ELDORADOS AND SEVILLES
Some De Villes, Fleetwoods, Eldorados or Sevilles equipped with a THM 440-T4 transaxle may experience loss of downshift to first gear or second gear
starts on take-off. This condition could occur all the time or intermittently.
The following procedure should be followed to diagnose a second gear start condition:
1.
Pressure test as described in the appropriate Service Information Manual. Ensure minimum line pressure is to specification. A high minimum line
pressure could result in "governor circuit flooding" and cause unwanted governor pressure. Refer to the 440-T4 Diagnosis and On-car Service in
the Service Information Manual for high or low line pressure diagnosis.
2.
Remove and flush governor assembly with clean solvent, then inspect for binding weights and/or mispositioned springs. Replace governor
assembly if necessary.
3.
Reinstall governor cover without the governor installed. Start the engine and move selector lever to the drive position. Stop the engine and reinstall
governor assembly. This procedure will help flush the governor passages of possible debris.
4.
Road test and verify transaxle operation.
If the condition of second gear starts still exists:
Figure 1 - Governor Assembly
5.
Install a 0-100 PSI pressure gauge at the governor pressure tap and monitor governor pressure while the condition is occurring (refer to Figure 1).
6.
If governor pressure is 3.0 PSI (21 kPa) or below at 0 mph (0 kmh), go to Step 9.
7.
If governor pressure exceeds 3.0 PSI (21 kPa) at 0 mph (0 kmh), install a known good governor assembly and reverify transaxle operation. If
second gear starts are still experienced, continue to Step 8.
