grinding noise when letting off gas

[cgmtboarder]

hey everyone. ive recently begun this problem that when im gasing it pretty hard and then let off of the gas to coast down to speed, something makes a rattling or grinding noise under the car. but it doesnt do it all the time. sometimes its lound other times i dont hear it. ive notice if i push in the clutch it goes away. anything ideas?

 

[Freeze]

u joints on drive shaft??

 

[Barracuda]

Does the sound get louder when you're deceling from higher speeds? try 60mph vs 80mph etc.

If it does, it's just like my new problem. Haven't been able to find time to check underneath the car just yet.

 

[Apeximprt2nr]

Do you have an upgraded clutch disk?

I would say it is normal. Probably has something to do with the stiffer clutch disk hub you have now. The tranny has what is called a 'sub-gear' integrated to the 3rd gear final drive. That is there to prevent gear chatter that in most cases can be felt and heard through the driveshaft under the car under light decel. Is the noise coming from the driveshaft? Unfortunately, when the b-shafts are removed, clutch has a stiffer hub, preloads are tighter in the trans, and the engine might have a little more harmonics, it is nearly impossible to get the noise to go away. The sub-gear gets overtaken by the added vibrations from the whole system and can no longer do its job very well. I have seen people with just the removal of the b-shafts run into this problem. My brother, before we knew what caused this, replaced his whole rear end assy, driveshaft, t-case, and trans to try to get rid of the problem. It was still there. It doesn't do any harm really. Over a long period of time you will see a little more t-case shaft spline wear and chatter wear on the hub and sliders in the trans, but that's it. The tighter you make everything from the t-case back, the quieter it will get though, so changing the driveshaft bearings, t-case coupler, tighten both the rear end and t-case, and reinstalling the balance shafts will help some. I would just learn to live with it though. That's just all part of having a car with modifications.

Jack

 

[Barracuda]

I Do.

Fidanza flywheel and fidanza 3.2 clutch kit.

Hey that could be my issue... or "issue". how about you, cgmtboarder?

 

[95gst16g]

My car made a horrid noise like that too.I traced it down to the A/C compressor.I dont know maybe the A/C clutch went bad.It started a very loud grinding noise then it started a little scraping noise at idle.I got sick of it and removed the belt....with my knife .Just a sugestion maybe look at that.Good luck

 

[cgmtboarder]

i cant tell really if its any louder at higher speeds or not. i notice it the most at 40 mph and up cause im not goin fast enough to not hear it. but its just really weird. i did just intall a new transmission and competition 2.1 clutch in my car though. all new fluids in tranny and t-case.

 

[MY1GDSM]

hey everyone. ive recently begun this problem that when im gasing it pretty hard and then let off of the gas to coast down to speed, something makes a rattling or grinding noise under the car. but it doesnt do it all the time. sometimes its lound other times i dont hear it. ive notice if i push in the clutch it goes away. anything ideas?

Its normal if it what I think it is
most likly Just harmonics from Say a lightwight flywheel or Urathane motor mounts
It's hard to remember But I don't think I ever remember hearing it untill I had either of the above or got rid of the Balance shafts pretty much on the same concept as Apeximprt2nr said with putting a BSE kit in

 

[8urwrx]

My car does the same thing. Balance shafts removed and also have a Fidanza aluminum flywheel. It sounds bad but I cant determine what it is. Car runs and accelerates perfectly.

 

[cgmtboarder]

i have no light flywheel or anything. just a racing clutch. i checked everything out today and everything seems to be solid. checked all the drive shaft and couldnt find anything. but if its nothing then i guess i wont bother looking for what it is

 

[brassc2007]

can you hear the noise when your sitting at idle with it in nuetral, and then if you push the clutch in it goes away?

 

[MY1GDSM]

I don't think that the TOB would/could make that much noise if it's what I'm thinking of

 

[Apeximprt2nr]

My car makes the same noise. B/S removed, Fidanza flywheel and 3.2 clutch. It's normal, just annoying.

 

[viprez586]

Same here, mods in profile. I just learned to live with it.

Everyone asks - whats wrong with my car once i decel.

 

[MY1GDSM]

People ask me the same thing
I tell Them"I worry when I don't hear the noises"

 

[cgmtboarder]

can you hear the noise when your sitting at idle with it in nuetral, and then if you push the clutch in it goes away?

no i dont hear it at idle. just when cruising down the road. it has to be something with racing clutches cause thats the only difference i can think of. but i guess its no problem. if i have my music up i cant hear it anyway

 

[Mr4G]

Do you have any kind of vibration at all. Jack the car up and wobble the wheels from top to bottom to see if it is a wheel bearing problem.

 

[Dsmj89]

I'm surprised no one mentioned a loose heatshield.
Check under your car and see if there are any loose heatshields above your exhaust piping that is making contact.

 

[AndrewD5418]

Driveshaft may need to be shimmed to be "straight". There's a guide on how to do it on galantvr4, it involves the spacer kit and using a level.

Maybe it's the rear diff?

 

[MY1GDSM]

Get some video of it with good sound and I bet we'll be able to figure out what it is

 

[cgmtboarder]

i checked the exhaust and heat shielding and nothing moves. it sounds like gears grinding or somethin. maybe rear diff. i can see if i can get a video but it may be hard to hear

 

[MyEclipse5]

Do you have any kind of vibration at all. Jack the car up and wobble the wheels from top to bottom to see if it is a wheel bearing problem.

You have time to post on the forums, but not to reply to my PMs?

 

[videogamemaster]

I had the same problem with my talon a while ago after installing an aftermarket clutch and lightweight flywheel combo. I think its simply the lightweight flywheel that causes the noise you are hearing. Like someone said in a previous post I would worry more when my DSM isn't making noises.

 

[Harriz801]

I have this same exact issue with my Talon, On decel, usually between 3,500 - 2,000 RPM range it makes a horrid sound that just sounds like harmonics through the car.

I myself am running without balance shafts, with a SPEC stage 2 clutch and an OEM flywheel.

If I get some time I will get some video on here.

 

[cgmtboarder]

ya mine is about the same rpm range and i deff notice it the most from 35 to 55 mph.