Why does my diff bang and clatter?

[Billy.Whizz]

Driving home from picking up my new car from CC I could hear a clattering metalic  sound when passing over anything other than a smooth surface, I thought it might be the hood sticks clanging together, it wasn't then I thought it may be the RARB it wasn't that either so because it was quite a loud noise i took it back to CC, it turned out to be the rear brake pads rattling about, so they bent the spring tensioner a bit more to hold the pads down in place and the problem has been solved.

[GulfSeven]

#25 Do you know when they started fitting these to factory cars. Would it be on my 2020 310R? Is there any way I can check?

[john hooper]

Thanks for the info. I would never of found it there.  

[ChrisC]

It wasn't in my kit delivered October 2019, it was in a kit delivered January 2021.  So sometime between those two dates.  The gearbox angle may be different between a Sigma and Duratec engine cars, so might not have the same impact as it did on my car.  
The funny thing was, after I discovered it, I spoke to Caterham Gatwick to see if it assist with my problem, and they where unaware of it at the time.

[ScottR400D]

The Duratec, certainly with a 6 speed slopes down by, nominally, 2 degrees at the front to aid hood clearance. 

The BMW diff, for unknown reasons slopes down by, again nominally, 4 degrees. It does look like it would require other compromises in its location to get it horizontal. 

If the Mazda box without a spacer is nearer to or is horizontal then the prop shaft flanges could be out of parallel by 3-4 degrees. The resulting variable rotational speed of the prop could then cause diff noise. IMO. Fitting the spacer could only help. 

I was told by RRT about the engine tilt. I 'asked an expert' at CC who answered "I have no idea' but subsequent measurements on my and other similar cars were consistently as above. It might not always be so. 

​The thing is that, supposedly, the Sigmas are mounted horizontally so you'd expect them to be worse, unless the increased power and torque of the Duratec plays a part, which could well be the case.