Constant Popping noise from rear of car

[skeevay]

Hi all,
I have an 03 Cobra vert that I have driven for only a few hundred miles so far. I love the car, but the loud popping noise from the rear is driving me crazy! The noise happens from rolling to 40mph and is completely random. Just driving in a straight line on smooth pavement under light power or decel or even rolling in neutral, I get a loud popping noise from the rear of the car. The noise is sometimes 2 or three different pitched pops in succession. Sometimes it makes the noise, sometimes not. I have had the car up on stands a dozen times pushing and prying on things. Everything seems very tight and I cant find anything loose to speak of. The car can be driven over rough surfaces and there are no rattles popping or any noises at all. The car has about 74000 miles and was bone stock when I got it (I did put on lowering springs, exhaust and new u-joints). The car is also very smooth driving at all speeds (no vibrations...etc.). Any ideas???!!! Any help would be greatly appreciated!!

 

[PowerWheels]

CV Joint?

 

[evil 03]

it could be the gears

 

[skeevay]

anyone else....does this sound like it could be a cv joint??

I did fix a rear diff cover leak and checked the gears at that time. They have nice markings and are tight. I wondered about the posi, but most I have experienced usually make noise while turning and you can "feel" the pop as well. This does it when going in a straight line, even after driving several miles w/out turning.

 

[skeevay]

Anyone else care to chime in with their 2 cents? I am trying to narrow this down a little so that I can save some money/ time! Thanks!

 

[corpsedub]

probably a combo of that crappy axlenut/spline stripping issue and the wrong size bolts in the IRS somewhere. mine pops alot too. sometimes it's the high pitch tink/po on takeoff. sometimes i get it in decel. sometimes i get the kerunk sound(metal shifting) when comming to a complete stop.

 

[spitin venom]

Do you have an aftermarket exhaust?
I was getting the same noises coming from mine. It ended up being the exhaust was too close to a bolt by the rear diff. The bolt is surrounded by rubber but it eventually wore the rubber down and started hitting the bolt.

 

[AaronK]

Do you have an aftermarket exhaust?
I was getting the same noises coming from mine. It ended up being the exhaust was too close to a bolt by the rear diff. The bolt is surrounded by rubber but it eventually wore the rubber down and started hitting the bolt.

What bolt? What part of the exhaust? I think I might have this problem. Thanks!

 

[spitin venom]

This is not my car but thank you too whoever owns it. You can see the bolts if you look at your car in the angle this picture is taken. There are 2 bolts that are surrounded by a rubber piece. This is where mine was hitting. It wears down the rubber and starts to bang against the bolt. It is loud and annoying. I thought I had a suspension problem.

Admire my ms paint SKILLZ

 

[skeevay]

Do you have an aftermarket exhaust?
I was getting the same noises coming from mine. It ended up being the exhaust was too close to a bolt by the rear diff. The bolt is surrounded by rubber but it eventually wore the rubber down and started hitting the bolt.

I have a Steeda cat back that I have checked over and over for any kind of interference, but will re-check this location. It is crazy because you can drive on the smoothest, nicest street with seemingly no suspension movement happening and it will still make this annoying popping.

probably a combo of that crappy axlenut/spline stripping issue and the wrong size bolts in the IRS somewhere. mine pops alot too. sometimes it's the high pitch tink/po on takeoff. sometimes i get it in decel. sometimes i get the kerunk sound(metal shifting) when comming to a complete stop.

The axle nuts seemed to be fine, but I did not take anything apart. Is there a common problem with these cv shaft assemblies?

 

[spitin venom]

I have a Steeda cat back that I have checked over and over for any kind of interference, but will re-check this location. It is crazy because you can drive on the smoothest, nicest street with seemingly no suspension movement happening and it will still make this annoying popping.QUOTE]

That is what mine does. It can be as smooth as glass but it will randomly pop/clank. It might look fine when looking at the clearance but don't forget that the exhaust moves around.

 

[XJRGUY]

My catback was causing the same problem.

Had it adjusted and noise went away.

 

[JB]

The axle nuts seemed to be fine, but I did not take anything apart.

I assume that "seemed to be fine" means you didn't actually check torque....


Get a torque wrench (capable of 250 ft-lbs or more) and then make sure those nuts are at 240

If they continue to loosen up, buy new nuts and use threadlocker

.

 

[KB04Cobra]

Do what JB said regardless, if that the prob of not. You don't want parts falling off your car when your driving.

 

[JB]

Yeah, it's a good thing to check ......I've seen many that were loose and it just tears them up if left that way

If damage has already been done to the splines it may be necessary to replace shaft and/or hub

We don't usually see problems with the CV joints unless you count breakage from hard launch or wheelhop

 

[skeevay]

Thanks for responses.

You are correct, I did not check to see if they were torqued to the proper specs. I will have to see if I can find a loaner torque wrench that goes that high and double check them.

 

[Troyz R Us]

Driveshaft bolts all tight?

 

[JB]

Take a look at the front subframe bolts as well

12MM fasteners from factory are sloppy fit and can actually wallow out the holes in the unibody

 

[JB]

Subframe-to-body bolts 76 lb-ft
Subframe-to-rear bracket bolts 76 lb-ft
Subframe rear bracket-to-body bolts 59 lb-ft
Shock absorber-to-lower arm and bushing bolts 98 lb-ft
Shock absorber-to-body nuts 30 lb-ft
Upper arm and bushing-to-subframe nuts 66 lb-ft
Upper arm bushing-to-knuckle nut 66 lb-ft
Lower arm and bushing-to-subframe bolts 184 lb-ft
Lower arm and bushing-to-knuckle nut 85 lb-ft
Toe link-to-subframe nut 35 lb-ft
Toe link-to-knuckle nut 35 lb-ft
Stabilizer bar bracket bolt 41 lb-ft
Stabilizer bar link nuts 35 lb-ft
Rear axle diff rear insulator-to-axle housing bolts 76 lb-ft
Rear brake disc dust sheild-to-knuckle bolts 89 lb-in
Brake line-to-rear brake caliper bolt 30 lb-ft
Parking brake cable bracket-to-lower arm bushing bolt 11 lb-ft
ABS sensor bolt 17 lb-ft
Axle shaft-to-hub retainer 240 lb-ft
Wheel nuts 95 lb-ft
Rear axle nut 240 lb-ft
ABS Sensor 17 lb
Tie Rod end 35 lb-ft
Shock Lower 98 lb-ft
Knuckle Upper 66 lb-ft
Knuckle Lower 85 lb-ft
Lug Nuts 95 lb-ft
Diff Housing Cover 24 lb-ft
Filler Plug 25 lb-ft
Pumpkin Front 52 lb-ft
Pumpkin Rear 76 lb-ft
Drive shaft 83 lb-ft

 

[FlaSeaDude]

Is Orville Redenbacher in your back seat? :shrug: :lol1:

Now, back to the serious stuff... :-D