Clunk Sound

[jmfrost]

I have a clunk sound and feel coming from my 2011 Mustang GT when I'm slowing down. It started after I put a Custom Steeda tune in it. I'm trying to find out if anyone else has had similar issues and or problems and what you did to get it to stop. Everyone I've talked to says its normal at the Dealership, but I know it isn't. Any help would be greatly appreciated.

SPECS:
2011 Mustang GT Prem. Kona Blue matallic
Automatic Trans.
Borla S-Type Cat-Back exhaust
Steeda lower trailing arms
Steeda 3rd Link
Steeda Cold Air Intake
Steeda High Tower Strut Brace
Custom Steeda Tune

 

[nocobrafornow]

have you checked the suspension parts you put on. what part of Ala. you in?

 

[MikeLTDLX]

What kind of clunk? Are you talking about from the driveline? There is a good deal of driveline lash with these cars. To avoid it, trying pushing in the clutch prior to letting off the gas when slowing, and engaging the gas right before releasing the clutch when moving. I find that will cut down on the driveline clunk quite a bit. If this is not your issue, please explain.

Mike

 

[MikeLTDLX]

Oh, and my rear suspension would clunk quite a bit going over bumps. I had to loosen up and re-torque my LCA relocation brackets as there was some bind there.

Mike

 

[Red Turtle]

MikeLTDLX, he has an Auto

Have you flashed the car back to stock to verify that it is indeed the tune? If so, I would then call Steeda with your findings.

 

[MikeLTDLX]

Duh, auto. LOL.

 

[racermatt]

I don't think the tune is the issue. But we would be happy to send you out another to try to address the issue.

The clunk you are hearing can be sometimes be heard when you add lower control arms and a upper 3rd link. As MikeLTDLX said there is a lot of driveline lash in these cars. Unfortunately when you improve and tighten up the rear suspension you may hear noises from the lash. A 1 piece driveshaft is the best remedy for this.

Feel free to give me a call or drop me a PM if I can be of more help.

 

[jmfrost]

I havent done anything with the suspension, other than the trailing arms and 3rd link, and I'm close to Dothan.

 

[jmfrost]

Just contacted mattracer, and he said I should have a revised tune by end of today latest being friday, I will post the results after.

 

[ViciousJay]

i get a clunk only when is stupid cold out side and im in a hurry

 

[jmfrost]

Future mod, Steeda Aluminum Driveshaft. Can't wait to have the money to get it.

 

[jmfrost]

And for the uneducated, what is LASH?

 

[five.slow]

check your panhard bar mine clunked on bumps and when i slowed done. come to find out when the dealership replaced my fuel tank they didnt tighten up my panhard bar.

 

[kevinp]

And for the uneducated, what is LASH?

Lash is just play or clearance, valve 'lash' for example is the clearance between the rocker arm tip and valve stem tip.

What you are hearing the trans downsifting into first while the car is moving, its a high numerical 1st gear and you are hearing the slack in the driveline getting taken up very quickly. Tunes that upshift harder tend to downshift harder and downshift into first at a slightly higher mph as well and that amplifies the 'clunk.'

 

[racermatt]

I just emailed you the tune. Please let me know how it works for you. Thanks

 

[grnenvy]

Hey

Your 100% right I have had Justin do alot of work on my trans tune to get it right. If u have a one piece DS it gets worse. That factory DS does a great job at softening noises.

Lash is just play or clearance, valve 'lash' for example is the clearance between the rocker arm tip and valve stem tip.

What you are hearing the trans downsifting into first while the car is moving, its a high numerical 1st gear and you are hearing the slack in the driveline getting taken up very quickly. Tunes that upshift harder tend to downshift harder and downshift into first at a slightly higher mph as well and that amplifies the 'clunk.'

 

[jmfrost]

Ok, just did the tune that mattracer sent me, and so far so good, no clunk sound or jerky type feel coming from the tranny but now it seems like its bogging down a little between 25- 41 MPH. Maybe its just becuase it hasn't fully intergrated into the PCM yet, but I'll update. I know Steeda said that you have to start the car drive the car for 10 min. in length for 10 min or longer 3 times before the program is fully intergrated into the cars computer. So I'll keep driving for about a week or so and update then.

 

[jmfrost]

grnenvy how would a one piece DS make it worse. I've been hearing that a one piece DS is the best thing you can do, and from what I've been hearing it also increases your horse power a little?

 

[kevinp]

A one piece driveshaft in mine made the clunks much worse, especially going from drive to reverse. The stock shaft is isolated with a rubber center bearing and the sheer weight of the thing soaks up the sound.

I'm not so sure a one piece shaft is the 'best thing you can do,' I've tried two now and I just put my stocker back in, a couple auto cars have been low 10s/high 9s with the stocker and thats good enough for me. Some M6 guys can tear up a one piece 4" chrome moly shaft with 400hp so it really depends what you are doing..

 

[jmfrost]

Ill only be tracking her everyonce and awhile. I just hate the fact that the car clunks and jerks. I think everyone on here was right about it not being a tune that is causing this, and I read on another forum on here, that a guy had to do something with ford3 different times, before he cut his losses and bought a 2012 GT Prem. Said something about he couldn't talk about it because he had to sign a contract with ford.