SPN 788 FMI 7 — Clutch actuator not responding mechanically
Applies to: Eaton · Volvo · UltraShift PLUS common
Clutch actuator not responding mechanically.
Your SPN/FMI rides along, so nearby mechanics see the fault before they quote you.
How serious is it?
Serious. Power derate likely — plan to stop soon.
Most likely causes
- Failed clutch actuator
- Clutch worn out
- Mechanical bind
- Clutch actuator
- Clutch worn
- Linkage
First moves (roadside)
- Inspect clutch wear
- Check actuator
- Inspect clutch
- Actuator test
Common misdiagnoses
- Replacing actuator when clutch is worn
FAQ
Clutch actuator not responding mechanically.
Serious — Power derate likely — plan to stop soon.
The most common cause is: Failed clutch actuator. Other possibilities include Clutch worn out; Mechanical bind; Clutch actuator; Clutch worn; Linkage.
Power derate likely — plan to stop soon. When in doubt, get a qualified mobile diesel tech on the truck before continuing.
Find a mechanic or related guides
General diagnostic guidance for heavy-duty diesel engines (Cummins, Detroit, PACCAR, Volvo, Mack). Not a substitute for a scan-tool diagnosis on your specific truck.