A/T - 440T4 TCC Applies With 1-2 Upshift

TSB 88-52 (Dec)

SUBJECT: THM 440-T4

PROBLEM: [1][2]Torque Converter Clutch Applies With 1-2 Upshift

CAUSE:
May be a missing, or mispositioned orifice tube screen




Figure 1 - Early Spacer Plate




Figure 2 - Late Spacer Plate

The orifice tube screen is used in mid-1985 and later transmissions. Refer to Figures 1 and 2 to determine if an orifice tube screen must be installed.

The orifice tube screen has a fine mesh screen on one end. The other end has a .030" orifice to allow a small amount of 2nd clutch fluid pressure to the TCC solenoid. (See Figure 2)

Failure to install the orifice tube screen will flood the TCC solenoid with 2nd clutch fluid pressure. The result is TCC engagement with the 1-2 upshift.

All 1984 THM 440-T4 transmissions have a TCC screen that does not use an 0-ring, or have an orifice. The condition listed above does not apply to these models.

PART NO. DESCRIPTION

8658060 Orifice tube screen, TCC solenoid
8658109 Seal, 0-ring (Orifice Tube Screen)