Drive Line Grinding Noise
 

I am the original owner of SPO1630. It was purchased new in 2003 and uses a 460 stroker. I now have 5,400 miles on the car. From the day I picked the car up at Legendary Motorcars there has been an intermittant grinding or rattling noise coming from the back end of the car. When I took the car for the final drive at Legendary, they told me about the strange noise. As I was driving home I heard the noise and stopped the car and looked under the back end. Nothing was visible. Since that time the car was back to Macro Autosports Canada for regular work and all upgrades that were available until 2007. (Macro was put out of business by Transport Canada about that time) Macro was unable to resolve the problem. It has been in the shop to get the shock tower kit from Performance Unlimited and nothing was out of alignment or loose. In about 2010 I called Len Scok the former owner of Macro. He was nice enough to return my call even though the car is long out of warranty. He told me again that every update from the factory was put on my car. The only thing he said was that the driveshaft is so short with a 460 that the angle to the rear end is extreme and it is probably the U Joints rattling. It does sound like U joints rattling and this may be the problem although the U Joints are not worn or loose. Does anyone have any thoughts or suggestions on how to resolve this issue?

Hi David,

Just curious…

Being intermittent, are there any identifiable driving activities or road characteristics that encourage this to present itself or worsen?

Are there any noticeable active rub/wear marks around the u-joint flanges from exceeding intended motion angles?

If not already, you may want to also try talking to someone like Denny’s Driveshafts. They supply Cobra driveshafts and may have helpful experience/advice. I had some specific questions recently and found them very patient and helpful with my many questions and part search/info.

Brent

The noise is intermittent and always at cruise. It does not happen under power. I will give Denny's a call. Thanks for your suggestion.

Have you inspected the rear hub bearings and tightness of axle nut? There was a known issue with the SPF cars, and your chassis falls within the problem range. SPF even issued a warranty and TSB for the repair. I would also inspect your rear suspension shock mounts as they are noted to fail in your chassis range as well. Not intending to pile on, your car may also suffer from rear CV joint failure. All of these issues as they relate to your chassis number range are documented on SCOF's membership site.

Tremec has a free app for your smart phone which will allow you to check your driveline angles and tells you whether they are acceptable or not. Just google 'Tremec Toolbox app' to find it.

jack up the rear of your car and grab one rear tire at a time there should be no side to side play on either wheel and if there is you probably have bad bearings or a bad hub

I don't have access to my notes here, but there was a problem with rear axle nuts at one point. there was a Service Bulletin made. Problem sounds familiar. Jack the car and do as indicated in a previous post. Try to move the tire and wheel. Check rear caliper bolts too.