Corvette Forum : DigitalCorvettes.com Corvette Forums banner

1 - 9 of 9 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #1
I need some help with a very aggravating problem.
I have a rattle sound coming from under the car. It rattles at idle in park, reverse, neutral, and drive.
The rattle goes away when I press the gas. Here's the details:

2006 Corvette Z51
39,000 miles
6 Speed Automatic
Stock engine and transmission

I have replaced all three torque tube bearings, both rubber bushings, the plate that bolts to the torque converter, torque converter, and transmission fluid pump. I also took the car to a transmission shop and had the transmission disassembled and inspected, they found no problems.
Does anybody have any ideas or suggestions as what it could be?
Any help is appreciated.
 

·
DC PIT CREW BOSS
Joined
·
39,679 Posts
If it does in fact rattle in park, put it on lift and get under it with a tube like a paper towel roll or a piece of PVC about 1½ - 2in diameter. If you could get something about 18"-24" it would work well. Put one end to your ear and listen to EVERY square inch of the undercarriage. Good luck with it
 

·
Registered
Joined
·
4 Posts
Discussion Starter #3
The rattle comes from the torque tube. I've checked it with a mechanics stethoscope.
It's the loudest from the rear bellhousing area. But it's noticeable at the front bellhousing as well.
Being that I've replaced all the bearings and bushings in the torque tube, as well as the torque converter and transmission fluid pump, I don't understand how the torque tube could be the cause of the rattle.
Is there anything else that could cause the torque tube to rattle? Perhaps something to do with the engine or harmonic balancer?
 

·
Registered
Joined
·
914 Posts
You should remove the rubber plug from the front bellhousing of the torque tube. Use a bore scope to see if the bearing on the propeller shaft is seated into the torque tube housing. If the splines on the propeller shaft did not fully slide into the splined coulpler on the back of the engine it can push the propeller shaft back and allowing the bearing to pop into the torque tube housing. I have just discovered this exact same condition in my 2008 a6 corvette.
 

·
Registered
Joined
·
4 Posts
Discussion Starter #8
Update: Problem Solved.

I had previously replaced the bearings and bushings in the torque tube, replaced the torque converter and the transmission fluid pump but still had the rattle at idle.

I have now replaced the entire torque tube assembly and the rattle is gone.

So, I don't know what the actual problem was...
perhaps the driveshaft in the torque tube was out of balance, or the rear bearing assembly was faulty, or where that assembly mounts in the rear of the torque tube. Guess it doesn't matter now, the problem is solved and I love my car again.
 

·
Registered
Joined
·
1 Posts
I need some help with a very aggravating problem.
I have a rattle sound coming from under the car. It rattles at idle in park, reverse, neutral, and drive.
The rattle goes away when I press the gas. Here's the details:

2006 Corvette Z51
39,000 miles
6 Speed Automatic
Stock engine and transmission

I have replaced all three torque tube bearings, both rubber bushings, the plate that bolts to the torque converter, torque converter, and transmission fluid pump. I also took the car to a transmission shop and had the transmission disassembled and inspected, they found no problems.
Does anybody have any ideas or suggestions as what it could be?
Any help is appreciated.
One idea comes to mind since I have an odd rattle that I can only hear while under my 1997 Regal LS 3.8L. Only 83K miles. It's not supercharged, this model engine, but there's a large cast iron arm that runs from the rear of the engine to the front of the engine in the lifter valley. If you line up, in your mind and physically, this arm, it is a lot higher than the camshaft gear so it is not driven by the camshaft in any way. Sooooo, there must be a gear inside the rear of the block that connects the rear of the camshaft with this cast iron arm that most likely turns the Supercharger on the 3800 GS model. Sort of like the old school days when the rear of the camshaft drove the distributor only you cannot see any gears connecting the two so it's not visible in the lifter valley with the intake manifolds removed. This makes me believe that there are gears that drive this cast iron arm in the rear of the engine that turns the supercharger on the models with a supercharger.
I too had zero issues with shifting up or down, OD disengages properly when you touch the brakes. Only odd thing, I bought some Lucas tranny additive on sale (NOT the thick goop) and added one to my 1991 Silverado and 1997 Regal. No issues on the Silverado but while in the Buick, after a 70 mile drive, I was taking the scenic route home, and the torque converter was not allowing a smooth unlocking when I or the cruise control hit the gas going up hills while trnny is in the OD position. No issues if I leave it in "3" only in OD position. If I push the pedal much closer to the floor so it jumps to 3rd instead of 4th then it is less likely to occur.
So, two different GM vehicles, my issue might be the torque converter, your noise might be a set of gears in the rear of the engine if it has a supercharger or at least has that cast iron arm for another model engine that is supercharged.
I guess you could experiment and add a bottle of STP to the motor oil and listen to what happens. In my case, drain the tranny to get that Lucas stuff out and refill with plain Dex III.
 
1 - 9 of 9 Posts
Top