#clunk

Mark writes:

Sajeev–

Here’s a weird one to test your skills of remote diagnosis. Fire up your Magic 8 Ball for this one.

Car: 2012 Mustang V6, manual gearbox, performance package (currently running some crappy General AS Max-03 tires), 33,000 miles. I’m the only owner; special ordered to get it just the way I want. Mods limited to a Shaftmasters one piece drive shaft ( scared into it by a few YouTube videos), a Draw-Tite receiver hitch to pull my one bike motorcycle trailer, and an 87 octane tune uploaded via SCT (on your recommendation). The car will go into a nearby Ford dealer for a look at this issue under warranty this coming Friday, but based on the “quality” of some of the work I’ve had done over the years, I thought it would help to give the techs some clues.

Problem: For the past few days, I’ve heard irregular “bangs” or “clunks” from under the car.

Longtime TTAC commentator Mikey writes:

Sajeev,

I bought a 2014 Impala LT with a 2.5 four cylinder, and a 6 speed auto. I’m a 60 year old guy, that’s driven more cars than I can count. I’m still in awe that the engineers have figured out a way to move a car with the weight and size of the Impala with a 155 cu. in. engine. I love the car, with its comfort, and size, it suits my needs perfectly. I’m getting great gas mileage, with mostly city driving. Were flirting with 5 dollars a gallon up here. I’m willing to sacrifice power for economy.

I’m rarely on the highway these days. However I do find that at highway speeds{ 75 mph or so} the slightest touch of the gas pedal, will cause a down shift. The tach will jump from 2200 up to the high 3000’s in an instant. Does the 6 speed down shift sequentially, 6 to 5? Or will it go back 6 to 4th?