A/T - Updated Line Pressure Testing
88cad03Bulletin No.: T-88-107
File in Group: 7
Number: 187
Corp. Ref. No.: 777148
Date: March '88
SUBJECT: 1986-1987 SERVICE INFORMATION MANUAL UPDATE INFORMATION - THM 440-T4
MODELS AFFECTED: 1986-1987 DE VILLES, FLEETWOODS, ELDORADOS, AND SEVILLES
FIGURE 1 - 1986 PRELIMINARY CHECK PROCEDURE:
FIGURE 2 - 1987 PRELIMINARY CHECK PROCEDURE:
FIGURE 3 - TRANSAXLE INTERNAL COMPONENTS:
FIGURE 4 - SHIFT SPEED CHART (ADDITIONS ARE SHADED):
FIGURE 5 - NEW THERMAL ELEMENT PIN HEIGHT GAUGE J-34094-A:
This bulletin is provided to update information contained in the 1986 440-T4 Automatic Transaxle unit repair section and the 1987 440-T4 Automatic Transaxle Hydraulic Diagnosis and Unit Repair Sections of the Service Information Manuals. Please update your 1986 and 1987 Service Information Manuals with the revisions provided in this Bulletin (refer to the chart below).
NOTE: When checking line pressure on a 1987 THM 440-T4 transaxle, it is important to follow the steps as described in the Preliminary Check Procedure in Figure 2. Using the TV cable to check maximum line pressures WILL NOT provide the accurate readings referenced in the range pressure chart. Since the introduction of the aneroid vacuum modulator, detente oil seats the #14 check ball against modulator pressure and then becomes effective on the line boost valve, in place of modulator pressure.
REVISED SERVICE MANUAL INFORMATION
BULLETIN
FIGURE MODEL YEAR SECTION PAGE FIGURE NUMBER
NUMBER
1 1986 7A1-Transaxle Unit Repair 440-T4-5 4
2 1987 7A-Hydraulic Diagnosis 440-T4-4 3
3 1987 7A1-Transaxle Unit Repair 440-T4-14 34
4 1987 7A-Hydraulic Diagnosis 440-T4-3 2
5 1986 7A1-Transaxle Unit Repair 440-T4-69 79
5 1987 7A1-Transaxle Unit Repair 440-T4-52 79