Gears Grinding?
Thread Starter
Pro
Joined: Dec 2003
Posts: 654
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From: chandler az
Gears Grinding?
I thought I would ask if anybodys heard of this.
From a standing start if I engage the clutch out hard I get what sounds like gears grinding. If I ease it out gently it's quiet.
This is the same for second gear as well from a standing start. I've tried readusting the shifter and it didn't help any.
There are no other noises once the car is moving whether I am up shifting or down shifting.
Am I mistaking this for a torque tube chatter or is this a sign the trans is going to go?
From a standing start if I engage the clutch out hard I get what sounds like gears grinding. If I ease it out gently it's quiet.
This is the same for second gear as well from a standing start. I've tried readusting the shifter and it didn't help any.
There are no other noises once the car is moving whether I am up shifting or down shifting.
Am I mistaking this for a torque tube chatter or is this a sign the trans is going to go?
Melting Slicks
Joined: Jan 2009
Posts: 3,181
Likes: 285
From: Puyallup Washington
The trans gears will grind when you move the shifter into gear, not when you let out the clutch, since the gears are already engaged. When you let the clutch out that is when things start turning. It would not be gears in the tranny grinding. The gears could be making noise but I do not think that would sound like grinding. I would look somewhere else than the tranny.
Tech Contributor
Joined: Aug 2008
Posts: 2,902
Likes: 21
From: Oak Hill Virginia
Probably... here's a partial quote from Eric D in another thread:
Propshaft
We need to at least touch on the subject of the propshaft. All shafts will have resonate points. These resonate points occur in torsion, and bending of the shaft. The frequency that this happens varies with stiffness. Stiffness is controlled by things like the shaft diameter and mass. Some of the possible excitation sources (what excites these resonate points) are shaft imbalance, and torsional inputs.
In any propshaft the design engineer may take different approaches as to where to place the resonate point. The designer can target a resonate point above the operating rpm range or below. Keep in mind this is always a balancing act between cost and functionality. In the case of the stock Corvette the design engineer choose to place the resonate point to a very low frequency. I’m sure you have heard the rattle during a slow launch from a complete stop or when shutting down the engine with the clutch engaged with the transmission in neutral. It really sounds bad. Even though it is mentioned in the owner's manual, a lot of first time Corvette owners will ask about it. The shaft passes through this resonate point at start while loads and speed are down.
Do you have a sound clip of the noise?
Propshaft
We need to at least touch on the subject of the propshaft. All shafts will have resonate points. These resonate points occur in torsion, and bending of the shaft. The frequency that this happens varies with stiffness. Stiffness is controlled by things like the shaft diameter and mass. Some of the possible excitation sources (what excites these resonate points) are shaft imbalance, and torsional inputs.
In any propshaft the design engineer may take different approaches as to where to place the resonate point. The designer can target a resonate point above the operating rpm range or below. Keep in mind this is always a balancing act between cost and functionality. In the case of the stock Corvette the design engineer choose to place the resonate point to a very low frequency. I’m sure you have heard the rattle during a slow launch from a complete stop or when shutting down the engine with the clutch engaged with the transmission in neutral. It really sounds bad. Even though it is mentioned in the owner's manual, a lot of first time Corvette owners will ask about it. The shaft passes through this resonate point at start while loads and speed are down.
