A/T - 440T4 Bind-Up In All Gears

TSB 88-33 (July)

SUBJECT: THM 440-T4

PROBLEM: Bind-up in all gears

POSSIBLE CAUSE: May have no clearance in 4th clutch pack

The earliest THM 440-T4 transmissions have a taller 4th clutch piston than later units.

Because of this 4th clutch, frictions are thinner on earlier transmissions. Using a later friction in an early transmission may cause the 4th clutch to drag, or cause a bind-up in all gears, including Park and Neutral.

The bind-up may not be apparent at first, since acceleration may be necessary to "feel" the bind-up.

To check 4th clutch pack clearance, lay the channel plate on a bench with the case side up. Stack 4th clutch pack into channel plate, just as it would be installed on final assembly.

Install assembled sprocket support onto channel plate, and secure it with at least two bolts.




Air check the 4th clutch piston, watching it stroke. (See Figure). Proper clearance is .030" to .080".

Note
Many larger vehicles use two 4th clutch frictions. Check that all models have clearance in the 4th clutch pack.