Fluid level low.

Add fluid to proper level. Refer to Transmission Fluid Check .

Fluid level high.

Drain fluid to proper level. Refer to Transmission Fluid Check .

The oil cooler lines are restricted.

1. Remove the restrictions.
2. Clean or replace the lines as necessary. Refer to Transmission Oil Cooler Line Replacement .

The torque converter has broken parts.

Repair or replace the converter assembly.

Refer to applicable Allison Transmission Service Manual.

The oil is aerated.

Check the following:

Internal leakage is slowing the oil cooling flow.

Overhaul the transmission.

Refer to applicable Allison Transmission Service Manual.