Auto Trans 'Quirk'?

Ecto1

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I'm getting a single bang and a single rocking of the car from side to side at start up in my '15 Ecoboob. It does it EVERY time I start the car. It never happens under any other conditions. Does this sound like it might be trans related (6R80E trans I believe)?

I had the dealer's shop evaluate it for me and they claim it's 'normal' for an aging ecoboob mustang. I think this is legalese for 'we have no fricken idea what's wrong'.

Could a sticking lock-up torque converter possibly make a bang at start-up? Is there anything obvious inside the trans or torque converter that might cause the car to rock side to side (1 time only) when the car is started?

I'm considering having the dealer's shop separate the torque converter from the flex plate and start the car for me and see if the bang goes away. But this is an expense I'd prefer to avoid if I can help it. And I'm sure they won't be too thrilled about doing it for me either.

Thx.
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Ock

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I'm getting a single bang and a single rocking of the car from side to side at start up in my '15 Ecoboob. It does it EVERY time I start the car. It never happens under any other conditions. Does this sound like it might be trans related (6R80E trans I believe)?

I had the dealer's shop evaluate it for me and they claim it's 'normal' for an aging ecoboob mustang. I think this is legalese for 'we have no fricken idea what's wrong'.

Could a sticking lock-up torque converter possibly make a bang at start-up? Is there anything obvious inside the trans or torque converter that might cause the car to rock side to side (1 time only) when the car is started?

I'm considering having the dealer's shop separate the torque converter from the flex plate and start the car for me and see if the bang goes away. But this is an expense I'd prefer to avoid if I can help it. And I'm sure they won't be too thrilled about doing it for me either.

Thx.
i am assuming they checked all the mounts/cross members?
 

cbdallas

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The rocking you get at startup is the engine moving on the mounts as it fires up. All cars with a longitudinally mounted engine do it to some degree, but as an example, a Mustang is going to do it more than a Lexus LS or Mercedes S, as they take every measure to isolate the driver from all things noise and vibration-related. My V6 does it more than my Ecoboost. My Ecoboost coupe (gone now) gave a slight bang since day one.

You may have worn engine mounts, which can get noisy when the soft material becomes hard, or just deteriorates. It's not an indicator of a transmission issue. Get an indy shop to replace your mounts, if it bothers you.
 
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Ecto1

Ecto1

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i am assuming they checked all the mounts/cross members?
I hope so. I also crawled around under the car before I took it to the dealer and tried horsing the trans cross member around but couldn't move anything. It looked like it was nice & tight. I also tried to examine the motor mounts but I couldn't really see anything. I could just tell that they were mounts.
 
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Ecto1

Ecto1

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The rocking you get at startup is the engine moving on the mounts as it fires up. All cars with a longitudinally mounted engine do it to some degree, but as an example, a Mustang is going to do it more than a Lexus LS or Mercedes S, as they take every measure to isolate the driver from all things noise and vibration-related. My V6 does it more than my Ecoboost. My Ecoboost coupe (gone now) gave a slight bang since day one.

You may have worn engine mounts, which can get noisy when the soft material becomes hard, or just deteriorates. It's not an indicator of a transmission issue. Get an indy shop to replace your mounts, if it bothers you.
Well ... You're the first eco owner that has admitted to a bang at start-up. That's reassuring. Makes the dealer's line about it being 'normal' a little believable.

As far as the car rocking goes none of my other longitudinal engines have done it. Or not that I've ever noticed. I've been buying cars since before there were transverse engines. 4-bangers, straight 6s, slant 6s, V6s, V8s, and even a straight 8 for a few months. Maybe the banging noise is just making me overly concerned and I'm paying more attention to what the car's doing when it starts.

If it's normal I'll cope. Thanks for confirming the dealer's story with at least one other example.
 
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