lots of rear end noise

[Torinalth]

hey guys,

i've been having these issues for a while and ignored it, but its finally grating on me and i cant sem to track it down. there is of course the clunk when i go from engine drag to acceleration. i think that is more or les normal, but it seems to be getting more and more pronounced. when i go over moderatly bad pavement my entire ass seems to rattle like its comming to pieces. i thought it was something inside the trunk so i stripped out all the lining to see if i can pinpoint it... from what i can hear it sound like its comming from under the trunk area.

this leads me to think the axle, all conection pieces, or possibly the tank holds? also it seems to pop if i go over a raised gradient like into a parking lot with a slight incline.. but only really does it if the right side goes up first... almost nothing if the left tire goes up first.

anything yall can suggest? i am going to tear out my entire differential and attaching pieces, and completely redo the rear suspension... but its going to take time, and i'd like to start at whatever is making this damn racket. thoughts? please!

Torinalth

 

[03gtmustang]

Stock exhaust?

 

[Torinalth]

aye, stock everything in that area... only mods in sig installed. the attaching hardware is tight and no clanging. that was my first think to check, as well as the easiest. H pipe seems to be clear of everything, and everything from there back is secure and clear.

T

 

[mustang70]

Check your control arms. The bushings might be worn out. Or the sway bar can be loose as well.

 

[Torinalth]

sway bar is tight, yanked on it hard.. didnt move, also tried to tighten the bolts but they didnt budge. as far as the bushings..... how should i go about that? just remove the arms and reinstall? i know a good bit about practical concepts of mechanics, so i can figure out installation of anything... but not always sure what i am looking at once i get to where i need to be

Torinalth

 

[mustang70]

You can unbolt each end of the control arms and drop it down to check the bushings. Or remove the whole arm. The upper arms you'll probably have to pull out to get a good look at them. And don't forget about the bushings in the rear end for the upper arms.

 

[Torinalth]

how can i tell if they are shot or not? my guess is they prolly are.... 78k on the car, and i dont drive the car like a civic.... so its seem its share of real driving.... sigh.... maybe i should just get my LCAs, and panhard first, then subs and TA and be done with the UCAs all together. bah, but then i need to get new springs to adhere to the TAs need for less rear roll... sigh.... cant do anything in small steps can you....

anything else aside from the bushings/arms i can take a look at that might cause this? prolly going to open up my differential this weekend. heard a weird sound like a washer going off balence when spun on a bolt when i went WOT on first today.... think i might have waited too long to start replacing things.

Torinalth

 

[mustang70]

If you look at the bushings they'll look cracked and probably missing some chunks. You can check the diff, but you saying that you hear the clunk more while going over bumps and stuff leads me to the suspension. And there really isn't much more then the control arms and springs to look at. Unless the shocks are also worn out. We had a dually that would wear out the shocks and start making a clunking sound. So that's something else to consider.

 

[Torinalth]

the ass squeaks when its the hotter part of the day when going over speed bumps.... thus is the thought at least my rear dampers are hosed.... plus just with the back seeming to go to hell in a junkyard i would not be suprised. i plan on bilstines once money allows..... sigh.

i might as well not even bother checking the bushings.... just replace the LCAs, get springs and dampers with new isolators, and try to systematically redo everything.

OH. i almost forgot.... i sometimes think that going ove some bumps it almost sounds like my damn springs are ratteling. is that possible?

T

 

[mustang70]

It could be possible. Especially if the isolators are worn out. Something else I thought of, if you've been hard on the car, it might not be a bad idea to check out the mounting points for the control arms. They're just tack welded to the body.

 

[trinity_gt]

Agree with mustang70:

Someone recently posted about noise in the rear and I suggested they examine the upper control arms and bushings. They found that the torque boxes on the body for the one of the UCAs had actually cracked and partially pulled away from the body, leaving one side basically just flopping around.

 

[triggz]

my rear end creaks and groans reallllyyy bad when i do a brake-stand. im terrified to crawl under there and look at my torque boxes. :x

 

[Torinalth]

ahhh lovely more money possibly i have heard of thhe torque boxes so many times but have never really equated it to anything i am familier with. i know with hard launches with power and slicks they can break, people recommend battle boxes... but what are they/where do i find them/how can i tell if they are hosed?

Torinalth

 

[trinity_gt]

but what are they/where do i find them/how can i tell if they are hosed?

They're the structure on the chassis where the upper and lower control arms for the rear suspension bolt in. They're reinforced, "box-like" structures to deal with immense suspension loads but also with axle wind-up caused by driveline torque and braking forces.

Follow your control arms to where they bolt to the chassis.

Get the car up on ramps or jackstands and crawl under it with a trouble light. Look carefully at the upper mounts...look for tell-tale signs of torn sheetmetal, broken parts (i.e. brackets pulled away from the floor boards etc....)

Go read this thread:

http://forums.stangnet.com/showthread.php?t=551176&highlight=torque+box

It shows pictures of the boxes and the damage you might see if yours are bad.

 

[Cobracanuck]

i just recently had this exact same problem.
after asking around here, i finally decided to bring it into a shop, and it turns out that it was indeed the differential is burned out.