Thunderbird V6-232 3.8L SC (1989)
Throttle Valve Cable/Linkage: All Technical Service Bulletins
A/T - AOD Harsh/Rough Shifts
Article No.
91-11-14
05/30/91
TRANSMISSION - AUTOMATIC - AOD - HARSH/ROUGH 3-4/4-3 SHIFTS
FORD:
1989-90 CROWN VICTORIA, MUSTANG, THUNDERBIRD
LINCOLN-MERCURY: 1989-90 COUGAR, GRAND MARQUIS, MARK VII, TOWN CAR
LIGHT TRUCK:
1989-90 BRONCO, E-150, F-150
ISSUE:
Harsh or rough transmission shifts in certain vehicles may be calibration characteristics of the AOD transmission split torque feature.
However some customer transmission shifting concerns could be the result of improper (TV) pressure or sticking control valves.
ACTION:
Diagnose and repair the transmission. Using the following procedures which have proven to be an effective sequence of repair and
significantly reduces the potential for unnecessary replacement of major components.
Before performing any transmission repairs, test drive the vehicle to verify the 3-4 shift concern. Some of these concerns may be related to "tip-out"
clunk due to an engine processor strategy and may be repaired as specified in TSB 90-17-4.
If the referenced TSB does not eliminate the concern, refer to the following repair procedure.
Diagnose and Adjust (TV) pressure.
Refer to Section 17 of the appropriate Car or Truck Shop Manual for service details in performing the following adjustment.
1.
Check throttle valve (TV) pressure and verify 33-34 PSI for passenger vehicles and 29-30 PSI for trucks. If TV pressure is not as specified, adjust
TV pressure as outlined in the appropriate Car or Truck Shop Manual.
2.
With TV pressure properly set, test drive the vehicle to verify if symptom still exists.
If the vehicle has not been corrected, proceed as follows:
Inspect and Clean Main Control
Refer to Section 17 of the appropriate Car or Truck Shop Manual for service details in performing the following repair.
1.
Throughly drain the transmission and converter.
2.
Remove the oil pan and main control assembly.
3.
Disassemble the main control and check for stuck valves. With the separating plate removed, check each valve for free movement, pay special
attention to the 2-3 capacity modulator, 2-3 TV modulator, and the 3-4 TV modulator valve. Using crocus cloth, clean and polish lands as required
and reassemble.
4.
Install new upper and lower main control gaskets.
5.
Torque main control attaching bolts to 85 in.lbs. +/- 5 in.lbs.
NOTE:
Target 85 in.lbs.
6.
Install oil pan using a new pan gasket and fill with Mercon/R transmission fluid to the proper level.
7.
Recheck TV pressure and re-adjust as required to establish 33-34 PSI for passenger cars and 29-30 PSI for trucks.
8.
Test drive to verify repair.
As indicated, the above repair procedure has proven to be effective with over 90% of the 3-4/4-3 shift concerns. However, in some circumstances, the
above procedure may not completely satisfy the customer concerns. In those instances, the 1991 Main Control may provide the required shift
improvements. Refer to the following AOD Main Control Complexity Chart for the 1989-1990 Main Controls and their equivalent 1991 replacements.
