Owners of 2005-07 4.0L Mustangs with manual transmissions may complain of a knocking or rattling sound under light acceleration. According to Ford, the noise is most obvious in 4th gear, with the engine rpm between 1800-2200 and the vehicle speed at approximately 45 mph. A resonance condition in the powertrain is the most likely source of the noise.
The fix depends on the build date of the car. For vehicles produced on or after Dec. 4, 2006, replace the flywheel with an updated design, part no. 8R3Z-6375-A. For vehicles manufactured earlier, install the new flywheel along with an upgraded clutch disc and pressure plate, part no. 7R3Z-7550-B and 7R3Z-7563-B, respectively.
Some 2002-06 1.8L Sentra models with RE4F03B automatic transmissions may produce a chirp-type sound as the transmission shifts from 2nd to 3rd gear. Nissan says the noise is most obvious on light acceleration, and is due to problems in the transmission's high clutch assembly.
Adding two bottles of a new ATF treatment, part no. 31003-31X61P, to the transmission should help eliminate the noise. Before adding the treatment, get the transmission to operating temperature, then check the fluid level on the dipstick. If the level is in the HOT range, drain about a pint of fluid from the pan to before adding the treatment to prevent overfilling.
Some 2004-06 Scion xA and xB models may suffer from damp or wet carpeting at the passenger side footwell. The problem typically occurs with the air conditioning on and is most likely the result of the evaporator drain hose falling off the drain tube. Installing a special clamp, part no. 88899-52150, onto the hose should hold it in place and prevent further troubles.
Before installing the clamp, however, peek under the glove box and take a look at the drain hose. If it's still on the tube, this information doesn't apply; continue searching for the source of the leak. If the hose is disconnected from the tube, install the clamp, making sure it's about 1/8-in. from the end of the hose. Now push the hose onto the drain tube far enough so that the clamp engages the tube. To complete the fix, release the holding clip on the clamp, then start the engine, turn the air conditioning system on and check for leaks.
“Factory Fixes” is written by Jim DePalma, a 30-year veteran of the auto repair business who has served stints as a service manager, parts manager and ASE-certified technician. His column provides vehicle manufacturers' authentic factory technical service bulletins (TSBs) that have been condensed for easier reading. Mr. DePalma advises that techs always check with a dealer or repair information system for the latest revisions before starting to work on a vehicle. He can be reached via e-mail at [email protected].