Is my Torque Tube going bad?
09-29-2023, 11:54 AM
#21
Intermediate
Similar issue
My 12 GS 6at, 32k mi.
i bought the car and found the following concern.
ONLY WHEN COLD, when you put the car in gear, there's a rattle/knocking sound that is coming out of the front bellhousing/flexplate area. I've verified the source using a Stethoscope. No question about where the noise is coming from.
It's a very specific condition that can almost always be attributed to a cracked flexplate.
But a cracked flexplate wont be temp specific.
I pulled out the TT, and fine tooth combed everything from the engine back. I was a transmission rebuilder for 20 years, so I know what to look for. Everything looked fine.
I put a dial indicator on the input shaft and found .013" runout but apparently that's normal.
The shaft itself was perfectly straight, so its apparently the way that the bearing/shaft assy sit in the housing?
I should have changed out the flexplate/clamp but didn't since it looked so good. No visible wear on the splines, no loose rivets. I looked everything over for like days.
New bearings and new OEM couplings, reassembled everything and the noise was unchanged.
The noise disappears after the car warms up and there's zero vibration at any speed.
I believe it's a case of tolerance stacking.
I may pull out the TT again to replace the flexplate but I'll probably just live with it since it's causing no damage.
Apparently flexplate issues were common on the C7, but I couldn't find any information about this very specific noise on a C6.
Hope this info is helpful.
i bought the car and found the following concern.
ONLY WHEN COLD, when you put the car in gear, there's a rattle/knocking sound that is coming out of the front bellhousing/flexplate area. I've verified the source using a Stethoscope. No question about where the noise is coming from.
It's a very specific condition that can almost always be attributed to a cracked flexplate.
But a cracked flexplate wont be temp specific.
I pulled out the TT, and fine tooth combed everything from the engine back. I was a transmission rebuilder for 20 years, so I know what to look for. Everything looked fine.
I put a dial indicator on the input shaft and found .013" runout but apparently that's normal.
The shaft itself was perfectly straight, so its apparently the way that the bearing/shaft assy sit in the housing?
I should have changed out the flexplate/clamp but didn't since it looked so good. No visible wear on the splines, no loose rivets. I looked everything over for like days.
New bearings and new OEM couplings, reassembled everything and the noise was unchanged.
The noise disappears after the car warms up and there's zero vibration at any speed.
I believe it's a case of tolerance stacking.
I may pull out the TT again to replace the flexplate but I'll probably just live with it since it's causing no damage.
Apparently flexplate issues were common on the C7, but I couldn't find any information about this very specific noise on a C6.
Hope this info is helpful.
09-29-2023, 08:45 PM
#22
Le Mans Master
Member Since: Nov 2007
Location: Wilkes-Barre Pa
Posts: 5,861
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https://rpmtransmissions.com/product...-rebuild-kits/
Rebuilding the torque tube isn't all that difficult. Just very time consuming getting it in and out of the car. Cost should be almost all labor.
Rebuilding the torque tube isn't all that difficult. Just very time consuming getting it in and out of the car. Cost should be almost all labor.
09-30-2023, 08:04 PM
#26
Instructor
