Mustang_Lover05

Hi all, my 2005 Mustang V6 auto makes a deep but not loud Da-Dunk sound on every shift. I have no clue why the car does this and it is starting to worry me, the car runs perfect fine and it doesn't seem to do the noise under full throttle unless i cant here it due to the engine noise. My whole family has been in the auto industry over 60 years and don't seem to think anything of the noise. I am just the worry type when it comes to my own car haha. Have ya'll ever heard of this or has it happened to any of you?

flyhigh@mach1

Well, how about either the transmission mount on the cross member, or driveshaft U joints. You say it does not make that sound under hard acceleration? I'd start there, along with checking trans fluid level. (that's another thread in its self!)

Mustang_Lover05

Where are those located? I obviously know under the car and probably under the transmission or attaching to the transmission but what do they look like? And do you mean to tighten them or replace them?

flyhigh@mach1

Well, are you mechanically inclined? The transmission mount is on the transmission crossmember. Check to see if the bolts are tight. The mount might be cracked..if so it will need to be replaced. If your unsure of what your looking at, take it to a shop so as to not do more harm than good!

Mustang_Lover05

I know how to so some basic things but I'm sure I can check to see if the bolts are loose and look at it all.

Mustang_Lover05

P.S- I have a bama sct tuner and I put it back to the stock tune and the thud/odd noise didn't occur, it only happens when I have it tuned, just found this out today does this seem normal to any other bama sct tuner users?

BroncoTrooper

Sounds to me like the transmission is just shifting harder when you have it tuned. The minivan settings that came stock don't let the car shift hard like that. I was quite surprised the first time I felt how hard the car shifts when I had it tuned (especially with the race tune).

157dB

Your driveshaft flange is loose.
Its the end by the transmission.
Mine was loose from the factory
and made the same exact sound
you are describing.
I would not suspect U-Joints unless
you are lowered and did not address
the pinion angle when the lowering
springs were installed.
Nor would I suspect the rear tranny mount.
Driveshaft flange(s) would be my educated
'across the internet' guess...

Mustang_Lover05

Ok i will try and jack the car up tomorrow if i can get time, is the flange closer to the engine side or the rear of the car? Should i just tighten them up?