Hi all,

Does anyone else have the following problem? Y/N answers are ok (trying to get a count)

Sorry it's a bit long... but I need help and want to be detailed.
I have a 07 S 6MT with prem, nav, tech, and 4was. I am still in the break-in period, so no hot rodding... yet.
I have this chirp and dull metallic click/clank noise coming from my rear-end/tire area when I accelerate from a stop or start to back up. (The chirp almost sounds like the chirp from the nav when shifting into reverse.) If I drive super slow, (worse than a grandma in a Cadillac) it doesn't do it. However, when I drive it a bit harder (still under 3500 RPM’s) it starts doing it again. People do notice my car... and not in a good way!
I took it to the dealer and of course and the service chick was baffled Then techs couldn't figure it out either. Said they hadn't had anything of the sort of nature yet. Since the tech said it was safe to drive, so she sent me home and told me that they would contact the factory techs the following day to see what's up and give me a buzz. After numerous calls on my behalf to get a call back she called me at 6:30 pm and said that the factory tech line said it's totally normal and all 6MT's do it. Then she pulled out the bull and said they had a G37 in the lot that did it earlier that day. Now I didn't fall out of the tree yesterday, and I do know a bit about cars. I informed her of this and politely asked her to tell me what the factory tech said it was. She suddenly said she couldn't clearly remember everything and would get back with me. That was about 3 weeks ago.

I would like to make this an open call for feedback (YES or NO will do too), so I can go back to the dealer and show them that this is not normal and not every G 6MT with or without 4was is doing this

Thanks to everyone in advance for your time and help.

 

no 4was on mine and no it doesn't do it.
The only chirp I get from the rear is from the tires when I take off hard

The 1->2 shift is hard when the car is cold and there is the 2nd gear clunk - but not like what you've mentioned.

 

I get a similar noise from my 6MT, sort of a clicking noise when starting to move at low speeds, been there from day one. It's especially noticeable when I back out of the garage because the walls reflect the noise back. This is a pretty typical sound made by Constant Velocity (CV) joints. I decided not to worry about it unless it got worse (which it hasn't in 5K miles).

BTW, mine is premium only, no 4WAS

 

So yours does it too... hmmm. I will be interested to see how many actually have this issue as well before I try and pursue this with the dealer.
It's just weird because I have never had a car do that (manual, automatic, rear wheel, or all wheel drive... I have had them all).
Thanks for the replys so far!

 

Er...I'm lost on this comment. Was under the impression CV joints only appear on FWD cars? Also, I can assure you that none of my past four FWD cars prior to the G did it...

 

Modern RWD cars with independent rear suspension (IRS) have the differential attached to the frame and drive the wheels through a pair of half-shafts from the differential to each wheel. The half-shafts must allow for angular displacement at both ends when the wheels move up or down but the differential remains fixed. Therefore some type of flexible joint that will transmit torque through an angle is used at each end of the half-shaft (unless it's a swing axle a la early VW/Porsche, but that's another story....). There is also a sliding splined joint at one end or the other to allow for small variations in half-shaft length as the suspension moves.

Like front drive, there can be no periodic rotational displacement between the differential and the wheel hub as the half-shaft rotates and the angles change, or you would feel a periodic surging. Hence the manufacturers use some type of constant [angular] velocity set-up, typically a "CV joint" at each end of the half-shaft.

You could think of the rear set up as very similar to FWD, except of course the outer joints don't have to accomodate anywhere near the angles that FWD wheel encounters because of steering.

This is all in contrast to the "solid rear axle", where the differential, half shafts and wheel hubs are a solid sprung unit. In that case there would be no need for CV joints. On the other hand, the single drive shaft from the transmission to the differential now has to accomodate angle and length changes as the rear axle moves around on the suspension. This is usually done via a pair of "U" joints 90 degrees apart. Although the drive shaft speeds up and slows down slightly with each revolution, the U-joints exactly cancel out the variation.

Sorry for the long-winded answer, hope it helps.

 

Very interesting, did not know that. Thanks for the level of detail, always like learning something new