ChrisC Posted May 13, 2014 Share Posted May 13, 2014 I have been using the GoPro in the Seven since I got it in December, but this was my first track day I have used it and it picked up a strange "chirp" sound while changing gear only when flat out. I didn't pick up on the noise, maybe because I wear ear protection, and I didn't feel anything funny or different with the gear changes. The car is a 2011 ex academy car, open sierra diff, 5 speed type 9, with a 150 kit fitted. My diff is not the quietest, and I am not worried about that, I think it could be a case of TADTS, or some weird resonance picked up by the GoPro, but I just wanted the BC community to confirm this. Video here PS The video was taken on the last session of the day, but all flat out changes from the day have this noise, also the second quiet gear change was done on the cool down lap from this session and the noise was not picked up on any gear change on the 100 mile journey home. Link to comment Share on other sites More sharing options...
shn7 Posted May 13, 2014 Share Posted May 13, 2014 First thought before watching the video was early sign of CRB failure but I'm not really picking up anything I can identify as such from the video. Does the sigma use the same CRB/Clutch fork as the K Series? If not then probably not the issue. Link to comment Share on other sites More sharing options...
ChrisC Posted May 13, 2014 Author Share Posted May 13, 2014 Not the same as a K CRB, its a hydraulic bearing. Wouldn't I hear a CRB problem with all gear changes, not just the high rev ones? Link to comment Share on other sites More sharing options...
shn7 Posted May 13, 2014 Share Posted May 13, 2014 I've had 2 K Series CRB's failed (two separate 7's) and both the initial symptoms were heard on high rev gear changes. Given it's a different setup in the Sigma I'm probably wrong and it's something completely different. Hope you find it. Link to comment Share on other sites More sharing options...
Martin J Posted May 13, 2014 Share Posted May 13, 2014 Your diff sounds just like mine, I to have a sigma. I think it's just noise from the diff. Link to comment Share on other sites More sharing options...
DJ. Posted May 13, 2014 Share Posted May 13, 2014 I see what you mean, I don't know what is making the noise, but I don't think I have heard it from my Sigma 125. If you want to have a listen to my car is a link to a lap of Goodwood. Not a lot of gear changing at Goodwood, but there is a maximum revs shift soon after the chicane. Duncan Link to comment Share on other sites More sharing options...
ChrisC Posted May 13, 2014 Author Share Posted May 13, 2014 Looking a the video very carefully, the noise is made as 4th is selected, not as the clutch is pressed and its pulled out of 3rd. I am checking all the videos now to see if its always 3rd to 4th. Link to comment Share on other sites More sharing options...
ChrisC Posted May 13, 2014 Author Share Posted May 13, 2014 Always 3rd to 4th (above 6500), its quiet if the change is made below 6. Its quiet 5th to 4th under braking. but also makes a noise as move out of 4th, but quiet into 5th. Can't help thinking I have a problem with 4th. Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted May 14, 2014 Share Posted May 14, 2014 Give Phil a call at Road & Race on 01959 525105 and describe the symptoms. He is a gearbox wizard. Link to comment Share on other sites More sharing options...
ChrisC Posted May 14, 2014 Author Share Posted May 14, 2014 My cars next priority is a trip to the Black Forest and the last thing I want as a worry from the gearbox, so a call to Phill is good advice. Thanks. Chris. Link to comment Share on other sites More sharing options...
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