guys,
i have on my 2003 gt steeda springs, rear upper and lower control arms, and front and rear swaybars on stock shocks and struts. when i slow down to turn (like my driveway, lowes, some fast food place, etc.) i downshift then into neutral, i get this rattling and knocking something fierce coming from what sounds like the back half of the car. i have had the trans. fluid drained and replaced to no avail. it usually happens when i downshift making a turn at low speeds. it did this a little before all the aftermarket stuff was added but not as loud. i had 2 shops check everything under and all parts are tight and seem to be in good working order. has anyone else had this happen?? not sure what to do. it just doesnt sound. any help?

 

I have had similar noise that turned out to be my axle backs needing tightening or adjusting away from the bottom of the trunk. When I would drive slow, turn left, or go up an incline it would occur. I've had to tighten/adjust twice in the last 6 months. It's worth thinking about.

 

sorry, the only thing i had that would give me a similar problem was the rear sway bar coming loose. when you figure it out post it up for future reference and best of luck.

 

is it a pop, clunk, grinding, what?

 

its a series of clunks, sounds mostly from the rear of the car more toward the center. mostly when i slow down and turn, thought it was only when i turn into an area with different elevation but i have had it on just a flat parking lot. we have a company here that is pretty good (they build race cars and modified cars for 2 ford dealerships here) and i had them look to see what it was. the guy couldnt find anything and everything under the car was tight and looked sound according to him and i was standing there with him. ive had 2 shops look at it so far and was thinking about a third...

 

What all modifications have you made to teh car? and I mean tell us everything you can possibly think of including repairs that have been done or anything of that nature.

My guess right this moment is (since you said you had lowering springs and also aftermarket control arms) and you said it happens when you downshift, you may have a tranny mount wore out and thats causing the noise when you downshift. I know my old 00gt would clunk from time to time when i would downshift quickly and the engine torque would slight move the exhaust and cause my x-pipe to bang the bottom of the floorpan slightly.

Something else to look at. the rear bump stop thats bolted to the bottom of the car directly above teh rear end differential housing, if your car is lowered, it will hit that piece of hard rubber alot sooner upon bumps and quick weight transferrs. This doesnt really make much sense since you say it happens on downshifting, and the cars weight should shift forward, but who knows.

 

on my 2003 i have steeda sport springs, steeda rear upper and lower control arms, steeda front and rear swaybar, flowmaster mufflers, steeda bump steer kit. original shocks and struts (car has currently 40k miles)
tranny fluid has recently been replaced with amsoil and g-force racing fluid mixed 3-1. it shifts great. mostly when i hear it is when i slow down and either shift into second or at low speeds take it out of gear into neutral. seems that most of the noise comes from when the car is in a turn or i am turning into driveway, restaraunt, etc. i havent had the time to put the car up on jacks to check if anything is loose or not. like i said when i had it up at the shop the last time, he said everything was tight from the tranny back. i dont think he checked the mufflers though. planning to upgrade to steeda exhaust next year, along with shocks and struts if needed and have money. anything i missed that you might need??

 

Im almost betting its a muffler bumping or something. If you can get under the car, look on the tops and top-sides of the exhaust pipes and see if theres and scruff marks

 

got under the car tonight. couldnt find any marks or anything on the mufflers or pipes, checked all the fittings and they were tight, checked the connections to the car and everything was good. only thing i can see was the right rear of the car is setting about 1" higher than the other side. i can get my hand turned sidways in the left side and same plus a little extra on the right. maybe something is not setting right. looks like i will have to get this looked at. ill let you know.

 

may be one of the rear springs not turned right in the mount and its causing to do weird things.

 

will be taking it to a local shop friday for them to look at it. maybe the third time will do the trick. i will let you all know how it turns out. i dont want to mention the shop that put it in..they are a pretty big suppier of mustang parts here on the east coast in my region. i still believe they can do a good job, maybe just caught them sleeping for a week while they had my car.

 

well i took the car in. had a guy ride with me for about half an hour, and of course the car wouldnt make the noise....(go figure). he put it up on the lift and checked everything. the rear swaybar was a little loose, and that the right muffler was close to the axle and/or frame, cant remember the verbage...anyway, couldnt find anything really sticking out to make the noise. he did say there was some small scuffing on the muffler when he looked at it. he checked the springs to make sure they were seated right also. so all this to say that we really couldnt pinpoint what exactly the problem was. we went to an open parking lot and did some aggressive figure 8's till we were dizzy and no noise. the dilema continues......

 

 

update. as of 10/20/08 i have minimal rattling coming from the back but now the springs squeak... it still does on occasion rattle, clunk whatever you want to call it. i will be putting it up on jack stands hopefully soon and removing the wheels to get a closer look at all the underside. will check every bolt, screw, plastic piece, and the exhaust to see if there is anything i can find. will let you know.