Driveline whine under load?

[Oldtimer]

When we drove my wife's new G8 home last weekend, we noticed a fairly high-pitched whine coming from under the car. It is obvious when the driveline is loaded, but disappears when the car is in a coast (say like if you have it in cruise control, and you go down a hill).

From my racing background, it almost seems like the differential isn't shimmed correctly to have the right amount of lash, but I don't know enough about these cars to tell if that is the case.

Anyone had this experience or give me a clue? I'm taking it back to the dealer on Monday, and would really like to be intelligent on it if I can be.

Thanks!

[JVH1982]

I get a whine through first and second, but I just attribute that to tight gears. The only thing I've noticed otherwise is that I can 'hear' when the car is in gear vs. neutral/park. No whine on higher gears to speak of.

[bigtreepu]

Oldtimer....Check this thread and see if this matches what you are experiencing.
http://www.forum.grrrr8.net/showthread.php?t=838&highlight=transmission+whine

[Oldtimer]

Oldtimer....Check this thread and see if this matches what you are experiencing.
http://www.forum.grrrr8.net/showthread.php?t=838&highlight=transmission+whine

That's close, although it's hard to believe that adding balance weights to a bracket solves what appears to be mechanical.

I'll let the Board know what the dealer says.

Thanks!

[-Ray-]

If it happens while you are on the interstate, it's most likely the high pitched whine that requires weights to reduce.

[TomPierce]

if it goes away if you a) put it in fifth or B) lift off the accellerator in sixth, then it is the sixth gear resonance that you have read about

[Oldtimer]

If it happens while you are on the interstate, it's most likely the high pitched whine that requires weights to reduce.

That's the situation, Interstate highway, cruise set at 77 mph, howl like a Banshee until you went down a hill, and then it would let up, but as soon as the engine picked back up, there it was again.

[Oldtimer]

if it goes away if you a) put it in fifth or B) lift off the accellerator in sixth, then it is the sixth gear resonance that you have read about

It's an automatic, and I had it in Sport, but the gearbox wasn't upshifting or downshifting, just stayed in sixth. I never put it in Manual to check it.

Does it matter it it's an auto or a stick?

Thanks!

[-Ray-]

Dealer will add weight to the transmission to fix it.

[bigtreepu]

It's an automatic, and I had it in Sport, but the gearbox wasn't upshifting or downshifting, just stayed in sixth. I never put it in Manual to check it.

Does it matter it it's an auto or a stick?

Thanks!

I don't believe it matters if it's auto or manual.

~Matt

[SRG963]

Added weight by dealer doesn't always work :(, I still have the whine depending on the weather.