Caterpillar Fault Code

Free · no signup

SPN 177 FMI 16

Transmission Temperature Alarm / Derate

System

Transmission

Symptom

Transmission Temperature Alarm / Derate

Diagnosis & fix steps

LOGIC: Torque Converter Oil Temperature High (Level 2). ACTION: Check transmission oil level and cooler bypass valve. Test torque converter lockup clutch engagement to confirm converter is not constantly slipping under load.

Red Seal field insights

Fluid Physics: High converter slip generates extreme shear heat in the hydraulic fluid, degrading friction modifiers and risking multi-disc clutch glazing.

Track this across your whole fleet

This code is free to read. AM Fleet Integrity lets your team log fault codes against assets, plus the full fault-code library, QR operator reporting, PM scheduling and predictive alerts. Start free — no credit card required.

Start your free trial

← All Caterpillar fault codes