Nissan Repair: Nissan Cefiro Brougham, nissan cefiro, torque converter

Question
QUESTION: I just bought a used, beautiful 2001 Cefiro 3.0 with only 38+K on the odometer. Whenever I start the engine and drive off, there is one loud noise from the auto gearbox. This only happens once, and will only recurr if I switch off the engine and repeat. My foreman has checked the gearbox and found nothing wrong. But the problem remains.  What gives? Is this a serious problem?

Answer:
Chee,

Check the motor mounts.  Specifically, the one at the rear is the one that will be making noise.  The motor mount should be electric and filled with ferro fluid.  That allows the mount to be soft at idle, no electrical power applied.  When you shift into gear it gets hard, electricity applied.  I bet when the mount is energized something is popping and causing the noise.  I do not think the noise is in the gear box itself.  Have your foreman get the car on a lift and get someone in the car and do the start thing and then shift into drive and have him watch for movement at the rear of the engine and also for loose exhaust components.  Those are the two most common causes of the noise.  Either metal touching or the exhaust being loose.


Sir, I have checked and my engine mounts are all rubber (they are in very good condition).  The noise persists, and I'm afraid that it may be someting serious.  However, except for that noise which my foreman suspects to be from a body valve (he has also checked and found all six (6) to be in good condition) opening upon start up and engaging gear.  FYI, the noise occurs once irrespective of whether you engage forward or reverse gear.  The auto gearbox also performs flawlessly at all speeds and conditions.  Please help!

ANSWER: Chee,

Have your mechanic check the torque converter to flexplate bolts and the driveshafts to see if there is excess clearance.  I say this since the motor mounts are good and the exhaust is not touching.  I have seen both before.

---------- FOLLOW-UP ----------

QUESTION: Thank you very much.  I will instruct my foreman to try.  For your information, when we get the car on a hydraulic lift and repeat the test, there is no noise - indicating that there must be a degree of loading on the gearbox before the problem occurs.  Thank you.

Answer
Chee,

Yes, the car needs to be on a drive on lift.  If the suspension is just hanging you will not get the loading or the noise.  This is driveline related and, as such, the tires need to be loaded to make, or simulate, the condition where the noise persists.