idle

iTrader: (5)

I know this isn't a CTS-V, but I do own a Trans Am Ls1 and was hoping good ole LS1tech could give me some advice on a transmission issue I'm having on the daily driver.

What occurs is, when I accelerate in 1st gear, around 2k rpms the drive shaft/transmission, directly underneath the armrest, begins to vibrate and shutter loudly. It is very obnoxious and has grown much worse over the past month. I'm stumped as to what it is, and can't get a good view with the exhaust right there.

I did just tighten an allen-head bolt underneath around the driveshaft-transfer case joint area.

My ideas….
-Something is loose with the trans/driveshaft/transfer case
-Something out of balance.

Thank you in advance!

FuzzyLog1c

iTrader: (4)

Does this problem occur in any other gear, and if so, what RPM?

idle

iTrader: (5)

it occurs in any gear now, although it used to be only 1, 2 and 3. I'm almost 100% certain it is the driveshaft, since when I accelerate from zero now, I hear a scrape-scrape-scrape then it evolves into a thud thud thud up to 2k and then after 2k it stops. I checked other sources and I guess this is the issue with the driveshaft in some bolts and a CV joint.

IdriveaV

iTrader: (5)

don't know what the driveshaft looks like or design, but if its anything like the CTS-V's mine made the same noise when the rear joint went bad.

Dmax/04V

Where is the transfer case on the AWD models located? Maybe something related to that seeing as GM has an ongoing issue with leaky and grenading tcases.

Stone17

iTrader: (3)

I would check the center bearing on the driveshaft.

I found this.

IdriveaV

iTrader: (5)

judging by that picture it looks like there might be 2 cv joints in that driveshaft. check both of them for play might narrow it down

kjr6306

iTrader: (1)

Just take it back to the stealership. Unless it has a ton of miles on it, the powertrain warranty will cover it.