A scraping or grinding noise coming from the driveline area during hard acceleration can be concerning for Ford Mustang owners. This article will examine the potential causes, diagnostics, and repairs for this issue.
Problem Explanation
The most common culprit behind a Ford Mustang driveline scraping noise under acceleration is a worn synchronizer shaft upper bushing. This bushing provides smooth engagement of the gears and dampens vibrations.
When it wears out, the loose fit allows the shaft to oscillate inside the transmission case, creating a scraping sound. This typically occurs when quickly shifting or punching the gas pedal from a stop.
Diagnostic Procedures
Gather required tools: Mechanist’s stethoscope, Pry bar, Borescope camera (optional)
- Test drive the vehicle and replicate scraping or grinding noise on hard acceleration, especially from a stop or during aggressive upshifts.
- Raise vehicle on lift.
- Locate synchronizer shaft upper bushing along the transmission tunnel.
- Insert pry bar near bushing location and pressure test – increased noise indicates issue.
- Inspect bushing physically and with borescope for wear or damage exceeding 0.1 inch clearance.
Repair Solutions
Replacing the upper synchronizer shaft bushing involves removing the transmission and disassembling the case. The bushing is pressed out and a new one installed with a hydraulic press. The updated bushing has revised dimensions and material for extended life.
Proper torques must be applied when reassembling. The transmission then needs topped off with the appropriate MERCON V fluid before test driving. Expect over 5 hours labor for the repair.
Ford Mustang Model Years Potentially Impacted
This issue is most common on 2005-2014 Ford Mustangs equipped with the Tremec TR-3650 5-speed manual transmission.
Vehicle Components Potentially Affected
The worn synchronizer shaft upper bushing directly causes the noise. But it can also accelerate wear on gears, blocking rings, shift forks, and bearings inside the transmission if left unattended.
Cost of Repairing
With 5+ hours of labor at around $100 per hour, plus transmission fluid and parts, expect to pay $750-$850 to fix the scraping driveline noise caused by a worn synchronizer shaft upper bushing. Using upgraded parts can increase longevity.
John Smith, a Los Angeles-based car specialist and automotive writer, boasts over 20 years in the industry. With a background as a master technician and a decade-long writing stint at notable automotive publications, John now shares his expansive knowledge on CarFinite, simplifying car maintenance for readers.