Mustang Owners Club Australia Forum

Technical & General Discussion Area => Tech Torque 1979 to 2014 => Topic started by: Giffo on March 22, 2015, 08:11:16 pm

Title: 2001 COBRA CLUNK??
Post by: Giffo on March 22, 2015, 08:11:16 pm
Okay it maybe heard before many times. But I am new and this is my first Stang.
I have a 2001 SVT Cobra Stang. DOHC 5 speed. It runs beautifully. But, when I first start off in 1st I get a big clunk. Then after each gear change a SLIGHT clunk in each gear. Even when throttle on and backing off. More than I have ever been used to after 20 plus vehicles (GMH and Fords) with all combinations. I have read various causes over the past month. Very confusing. Obviously USA Stangs are, I believe, slightly different. AU Falcon rear end to a degree I have read.
I have jacked mine up and felt the Uni's which felt tight. The IRS drive shafts felt good. Only bit of play I felt was the usual through the diff when no pressure when jacked up.
The gearbox feels great and tight.
So, where am I? Have read tonnes of web threads on many many forums. is the Australian 2001+ mustang Cobras built different in the rear end to comply to Aussie standards???
I hear the differential bushings are a main factor. And in the mix the rear IRS bushes, IRS frame etc etc etc.

So, I have put it out there. Is there a cure for the 2001 Mustang Cobra CLUNK??

And to add to that, is there a GOOD mechanic in Northern Sydney that can actually diagnose the problem rectify it without trading in a lung or kidney!

Apologies if this has been flogged to death before. Just cant find a real remedy here in Oz.

 :nopity:
Title: Re: 2001 COBRA CLUNK??
Post by: evan on March 23, 2015, 07:34:58 am
Have you checked your engine mounts? Pop the bonnet, handbrake on, put it in 1st gear, ease the clutch out & see if the engine lifts excessively. Try the same in reverse.

Evan.
Title: Re: 2001 COBRA CLUNK??
Post by: Giffo on March 23, 2015, 03:14:48 pm
Have you checked your engine mounts? Pop the bonnet, handbrake on, put it in 1st gear, ease the clutch out & see if the engine lifts excessively. Try the same in reverse.

Evan.

Hi Evan, yeah checked multiple times. All good there.
Sure its in the rear.

 :thumb:
Title: Re: 2001 COBRA CLUNK??
Post by: GLENN 70 on March 23, 2015, 03:21:02 pm
Simple fix ,sell it and buy a early model and have many clunks  :grin: . It might be like the later model falcons like the FG series ,the clunk in the rear end from the top bush in the diff cradle .  Common problem with those s that's for sure .
Title: Re: 2001 COBRA CLUNK??
Post by: dyates on March 23, 2015, 06:00:58 pm
I am with Glenn,if everything checks out and there is nothing that is obviously going to fall out live with it.Only when the clunk becomes becomes a bang followed by a loud scraping noise should the alarm bells go off.
Title: Re: 2001 COBRA CLUNK??
Post by: FB.65.68.70 on March 24, 2015, 06:14:30 am
Giffo,
I have a 2002 cobra and it had the same clunk, when we got under it we found a fair amount of backlash in the diff , it used to drive me nuts in peak hour traffic because its far more pronounced in the lower gears.  I took it to a mate in melb who is a diff specialist and from memory they shimmed the side gears and it made it a lot better.
Title: Re: 2001 COBRA CLUNK??
Post by: Giffo on March 24, 2015, 02:40:45 pm
Giffo,
I have a 2002 cobra and it had the same clunk, when we got under it we found a fair amount of backlash in the diff , it used to drive me nuts in peak hour traffic because its far more pronounced in the lower gears.  I took it to a mate in melb who is a diff specialist and from memory they shimmed the side gears and it made it a lot better.

With what knowledge I have gained over the years and after checking the usual check points I am leaning more towards the diff as well. Same issues as you stated. Will get it checked out when I can find a good mechanic in Sydney near my area.

 :thumb:
Title: Re: 2001 COBRA CLUNK??
Post by: jiffy on March 24, 2015, 03:51:30 pm
ok - interesting - I'm going to get my rear rebuilt shortly - going from 3.27 to 3.73 gearing, so any info you have about the side-gear clearances/dimensions etc would be appreciated....
Title: Re: 2001 COBRA CLUNK??
Post by: Giffo on March 24, 2015, 05:58:03 pm
Found this video clip on YouTube outlining an owners Mustang 2001 Cobra clunk

https://www.youtube.com/watch?v=o5aPlPQH8a4 (https://www.youtube.com/watch?v=o5aPlPQH8a4)
Title: Re: 2001 COBRA CLUNK??
Post by: Giffo on September 22, 2015, 05:37:13 pm
Hi all, I purchased a full suspension rubber kit and replaced most of the rubbers and ball joints etc. Including subrame and diff bushe.
Guess what........................ NO CLUNK and no rattling. Absolute dream to drive now. Smooth all over.
Will be replacing cross axis joints on the IRS later on. Maximum Motorsport supply good kits as well as CJ Pony.
New shocks and springs going in soon. Nearly rebuilt all.

Stay tuned.....
Title: Re: 2001 COBRA CLUNK??
Post by: Paul Clark on September 23, 2015, 05:19:31 pm
Seems to me that ever since you bought this car you havn't had your hand out of your pocket, must have been a beaut.
Title: Re: 2001 COBRA CLUNK??
Post by: Giffo on September 23, 2015, 06:35:28 pm
Yeah might seem like it. I paid a good price for her. I am a bit of a fanatic and want her to be in mint condition mechanically.
To buy just a few parts here and there and pay exchange rates and postage costs from USA I thought might as well replace all suspension rubbers as cheaper and it will last another 100,000 kms. Also wanted to lower her a bit as her private bits are showing she is that high :)
This has been a childhood dream and I finally have it. So to spend some bucks making sure she is all good it is worth it.
Even after I have finished all what I wanted to do I would have still only spent $28,000 and that's with the buying price. Well worth it don't you think??


Seems to me that ever since you bought this car you havn't had your hand out of your pocket, must have been a beaut.
Title: Re: 2001 COBRA CLUNK??
Post by: mwizz on September 23, 2015, 07:32:26 pm
Good decision replacing all of the rubbers
Title: Re: 2001 COBRA CLUNK??
Post by: jiffy on September 24, 2015, 09:00:49 pm
I got the gears replaced - and they replaced the rubbers holding the diff into the cradle, and the result is better than before, but then it wasn't too bad beforehand. The gear ratio has made a big difference to general drivability and it's certainly quicker if I get traction in 1st n 2nd.
Title: Re: 2001 COBRA CLUNK??
Post by: Giffo on September 24, 2015, 09:34:00 pm
Sounds good Jiff. Where did you get the gears from? Cost much to buy and install?

Title: Re: 2001 COBRA CLUNK??
Post by: jiffy on September 25, 2015, 11:07:15 am
Got the gears from Ford Racing in the US, they were cheap (compared to Oz prices) - about $150 from memory.
Centre and LSD needed to be rebuilt - cost a pretty penny - about $1100 to get them fitted, centre rebuilt, put in new bushes.
Title: Re: 2001 COBRA CLUNK??
Post by: Giffo on September 28, 2015, 06:31:23 pm
Money well spent??
Title: Re: 2001 COBRA CLUNK??
Post by: jiffy on September 28, 2015, 11:24:56 pm
I does make me smile - getting on it in 2nd and spinning up the tires...
Title: Re: 2001 COBRA CLUNK??
Post by: Giffo on November 26, 2015, 03:57:08 pm
Money well spent??

Hi Jiffy, need your help. After replacing all the above bushes etc there is still a slight clunk which I believe is in the diff. Are there any diffs in Oz that would be the same? What is the standard diff for this model? Anyone in Sydney that does diffs for Mustangs?
Other than that she is running really well.
Thanks in advance.
Title: Re: 2001 COBRA CLUNK??
Post by: Giffo on November 26, 2015, 04:40:02 pm
Hi Jiffy,

Is this all I need or more?

http://www.ebay.com/itm/Ford-Racing-8-8-Rear-End-3-73-Ratio-Ring-Pinion-Gears-Kit-M-4209-88373-/171179716851?fits=Year%3A2001 (http://www.ebay.com/itm/Ford-Racing-8-8-Rear-End-3-73-Ratio-Ring-Pinion-Gears-Kit-M-4209-88373-/171179716851?fits=Year%3A2001)|Make%3AFord|Model%3AMustang|Submodel%3ASVT+Cobra|Engine+-+Liter_Display%3A4.6L&hash=item27db1b30f3:g:FEQAAOSwstxVOkgC&vxp=mtr
Title: Re: 2001 COBRA CLUNK??
Post by: Giffo on November 26, 2015, 04:51:31 pm
OR MAYBE THIS?

http://www.ebay.com/itm/OEM-NEW-Ford-Racing-Traction-Lok-Limited-Slip-Differential-8-8-31-Spline-Case-/251472593952?fits=Year%3A2001 (http://www.ebay.com/itm/OEM-NEW-Ford-Racing-Traction-Lok-Limited-Slip-Differential-8-8-31-Spline-Case-/251472593952?fits=Year%3A2001)|Make%3AFord|Model%3AMustang|Submodel%3ASVT+Cobra|Engine+-+Liter_Display%3A4.6L&hash=item3a8cef4420:g:Yn8AAOxyRhBSxGq6&vxp=mtr
Title: Re: 2001 COBRA CLUNK??
Post by: jiffy on November 28, 2015, 06:34:16 pm
No on both counts. I have a different drive train to you - different engine and more importantly a different gearbox with different ratios. 3.27 is not a bad ratio given how low 1st gear is on your original box. I wouldn't go higher in the rear than 3.55, and I wouldn't change it at all if I was you. The engine management system is more responsible for the driveline harshness than you'd think.
Title: Re: 2001 COBRA CLUNK??
Post by: Giffo on November 29, 2015, 11:03:41 am
Gotchya.

 :ouch: