First step is to scan for codes, Autozone will scan it free, write down the codes and post them here.
There is a TSB on your tranny but for a different problem, may or may not be related.
SHUDDER ON ACCEL - POSSIBLE WRONG TRANS CROSSMEMBER ASSEMBLY INSTALLED (EXCLUDES GT 500) TECHNICAL SERVICE BULLETIN Reference Number(s): 08-23-4, Date of Issue: November 24, 2008 FORD: 2005-2009 Mustang Related Ref Number(s): 08-23-4 ARTICLE BEGINNING ISSUE Some 2005-2009 Mustangs vehicles (Excludes GT 500), equipped with either a 4.0L or 4.6L engine, may exhibit a heavy driveline shudder on acceleration from a stop or between 3-15 MPH (5-24 Km/h). On 4.0L engines there may also be an above average engine presence. The wrong transmission crossmember assembly may have been installed from the factory Similar complaints may also occur if the transmission crossmember and transmission support insulator were improperly reassembled after transmission removal. ACTION Follow the Service Procedure steps to correct the condition. SERVICE PROCEDURE Inspect the transmission crossmember assembly orientation. ( Fig. 1 ) 1. Fig. 1: Transmission Crossmember Assembly Orientation 4.6L V8 vehicles - Transmission crossmember hump should extend upward. Transmission support insulator (trans mount) should have a white or yellow paint dot. " 4.0L V6 vehicles - Transmission crossmember hump should extend downward. Transmission support insulator (trans mount) should have a blue paint dot. " NOTE: EXHAUST MOUNTS AND ISOLATORS, SHOWN IN Fig. 1, WERE PRODUCTION ASSEMBLY AIDS AND ARE NOT REQUIRED. THEY WERE DELETED ON VEHICLES BUILT AFTER 12/03/2007 AND MAY HAVE ALREADY BEEN REMOVED PER TSB 08-3-4 . If the vehicle is found to have the wrong transmission crossmember, then remove the transmission crossmember per Workshop Manual (WSM), Section 502-00. 2. Remove the transmission support insulator (transmission mount) from the transmission crossmember. 3. If present, remove and discard exhaust mounts and isolators from the transmission crossmember. The transmission crossmember exhaust mounts and isolators are a production assembly aid and are not required. Do not cut off the hanger rod from the exhaust system. 4. Orient the original transmission crossmember to match engine. ( Fig. 1 ) 5. Install new engine-specific transmission support insulator (transmission mount) onto transmission crossmember. ( Fig. 1 ) 6. Torque transmission support insulator (trans mount) nuts to 52 ft-lb (70 N.m). 7. Install the transmission crossmember per WSM, Section 502-00. 8. NOTE: DO NOT REINSTALL TRANSMISSION CROSSMEMBER EXHAUST MOUNTS AND INSULATORS. Bend exhaust hanger rods to a horizontal position to create approximately 2" (50 mm) clearance to the transmission crossmember. ( Fig. 2 - Fig. 3 ) 9. Fig. 2: Bending Exhaust Hanger Rod Fig. 3: Exhaust Hanger Rod Clearance To Transmission Cross-Member Verify the exhaust system is properly aligned by measuring the distance between the exhaust pipe and floor pan (behind the catalytic converter). The distance should be 2" +/- 0.5" (50 mm +/- 13 mm). If not, then re-align exhaust system using procedure in online WSM Section 309-00. 10.
Sunday, May 24th, 2009 AT 9:03 AM