Drivetrain noises...Any ideas what it is?

[0-60B4U]

I recently purchased this car and I'm starting to notice a thump in the rearend of the car when shifting gears. It does it in every gear when you release the clutch and will even do it when stopped. When I'm stopped at a stop light I can push the clutch in and shift into gear and it makes a thump. Any ideas what this could be? Also, the car has a Spec 3 clutch that shutters sometimes when you feather the clutch out. Is this common because it doesn't seem right to me. Any help would be appreciated.

 

[SVTDice]

Yeah, These cars are known for it. Here take a look at this and see if this is the problem your talking about, The guy found a fix as well.

http://www.svtperformance.com/forums/driveline-216/760059-rear-end-thump-bang-etc-fixed.html

 

[QuickV8]

mine only thumps when i let off the clutch pedal too fast. thats normal right?

 

[0-60B4U]

Yeah, These cars are known for it. Here take a look at this and see if this is the problem your talking about, The guy found a fix as well.

http://www.svtperformance.com/forums/driveline-216/760059-rear-end-thump-bang-etc-fixed.html

Thanks for the info. :beer: I've had a couple people tell me that a FTBR bushing kit is a must. Have any ideas on the clutch shutter? Tranny Mount maybe?

 

[03svtcobracoupe]

I'm having the same issue just bought the car last week.... the washer mod that he talked about in that thread.....

has anyone else tried this ? what he says make sense i can't really picture it but im sure on a lift i could quickly see the problem..

 

[0-60B4U]

I'm having the same issue just bought the car last week.... the washer mod that he talked about in that thread.....

has anyone else tried this ? what he says make sense i can't really picture it but im sure on a lift i could quickly see the problem..

Jimmysidecarr posted "Pinion bushings.(the two eyelets on the front of the diff housing and Aluminum bushings closest to the pinion flange pictured below)

These are the ones that without a doubt, get the hottest and by now just about every IRS Cobra out there has probably got worn out, looser than ever bushings.

OP's solution is obviously the low buck version, and hopefully his pinion angle is OK.

Not only do they clunk but they also contribute to wheel hop.

Here is the solution I used. http://fulltiltboogieracing.com/"

Hope this helps you!

 

[01Jes]

I still have it also even after bushings, shims, n etc..... Just somthing to live with. Wheel hop is minimal now with the bushings though. My 01 also had the clunk, just somthing to live with.

 

[03svtcobracoupe]

which kit did you use to fix the clunk...? i think my bad clutch isn't helping the situation tearing that apart this weekend hopefully

 

[03svtcobracoupe]

I still have it also even after bushings, shims, n etc..... Just somthing to live with. Wheel hop is minimal now with the bushings though. My 01 also had the clunk, just somthing to live with.

Im starting to realize that there are so many things that could cause the clunk and its almost certain to happen with any of these cars... but for what it is worth i ended up saving about 3k off the price tag of the car because they didn't want to have to deal with it !

 

[2003SLVRSNAKE]

My car made similar noises after I installed my Spec 3+. Some days, I thought it was the transmission other days I thought it was the rear. I was paranoid. I'm thinking it's your clutch. Like everyone says, just part of owning the car.

 

[Jimmysidecarr]

I am willing to bet, that I could get into any Cobra with an IRS, stock, rebushed shimmed or what ever, and I would be able to drive it and have it make zero clunk, or a big clunk.

Even though loose wiped out bushing and wheel hop are in fact very bad, learning to drive around the Cobra clunk will make your ownership experience a much more enjoyable one.

 

[TVSCobra]

Full Tilt racing bushings only! Had MM poly diff bushings, they sucked! Replaced them with the FTBR diff bushings and the car is completely different. No clunk at all and my high speed vibration is gone. I was really suprised how shitty my rear MM poly bushing looked after only 20k miles. What a piece of shit bushing. MM poly diff bushings are garbage.

 

[01Jes]

Full Tilt racing bushings only! Had MM poly diff bushings, they sucked! Replaced them with the FTBR diff bushings and the car is completely different. No clunk at all and my high speed vibration is gone. I was really suprised how shitty my rear MM poly bushing looked after only 20k miles. What a piece of shit bushing. MM poly diff bushings are garbage.

Interesting did you have the poly in the control arms or subframe?

 

[03svtcobracoupe]

I am willing to bet, that I could get into any Cobra with an IRS, stock, rebushed shimmed or what ever, and I would be able to drive it and have it make zero clunk, or a big clunk.

Even though loose wiped out bushing and wheel hop are in fact very bad, learning to drive around the Cobra clunk will make your ownership experience a much more enjoyable one.

noticed quickly you could drive around it... it would just be nice if when i was feeling lazy i didn't have to worry about making a big clunk infront of my buddies

 

[01Jes]

noticed quickly you could drive around it... it would just be nice if when i was feeling lazy i didn't have to worry about making a big clunk infront of my buddies

I was about to post that. It can be done but after a 12hr day of work:sleeping:

BTW Maximum MM upgraded to delrin which is in the car due the poly bushings going bad in the control arms. So far so good:shrug:

 

[cobracide]

Search "the clunk" 14mm bolts. [ame="http://www.google.com/search?sourceid=chrome&ie=UTF-8&q=site%3Asvtperformance.com+%22the+clunk%22+#sclient=psy&hl=en&source=hp&q=site:svtperformance.com+%22the+clunk%22+14mm+bolts&pbx=1&oq=site:svtperformance.com+%22the+clunk%22+14mm+bolts&aq=f&aqi=&aql=&gs_sm=e&gs_upl=5864l8756l0l8878l11l11l0l0l0l0l202l1392l2.7.1l10l0&bav=on.2,or.r_gc.r_pw.&fp=81eba942b626e508&biw=1318&bih=1048"]HERE[/ame] Works for some, bushings a good idea too.

 

[03svtcobracoupe]

everyone seems to suggest the 14mm bolt and the diff mounts. i think for me i'll try those and see if i can't diagnose the problem from underneath the lift.