clonking from rear 420 r 2000 miles pulling away slowing down really bad noise what can i do

[Limitless]

Time to put the kettle on...

[Jonathan Kay]

Was it running normally before that?

Any recent work?

Where is it now?

Jonathan

NB: Posted as a blog on 13 April:
https://www.caterhamlotus7.club/blogs/clonking-rear-420-r

[Wrightpayne]

Nut and bolt check everything to ensure nothing come loose.

Check for play in wheel bearings, driveshaft joints, prop shaft joints.

Report back findings.

[Dixa1225]

First thing I would check are the A frame bolts to the dedion tube. 

[Andy135]

Any chance of recording the noise and posting up here, assuming it can be done safely? Record a video on your phone and upload to YouTube for us to listen to? You may well get more accurate advice by doing so.

[Andy135]

For what it's worth I agree with #4, check all joints for play, then check wishbone/A-frame/diff bolts are tight.

[ScottR400D]

Yes, check all those mounting fasteners. Also make sure there's a decent preload on diff still but I would think more likely fasteners somewhere. 

[John Vine]

You say in the blog post (#3) "just purchased".  Was that with a warranty?  If so, it would be prudent to explore that.

JV

[Revinslevin]

Had exactly same problem with my factory built 420r which I received in January , took it straight back ,turned out to be an unsecured handbrake cable hitting against the tunnel,hope yours is a simple as fix

[anthonym]

I had that on my year 2000 K, terrible noise, and it was the diff bolts, couple of minutes to tighten them. 

[7 wonders of the world]

I used to find the lower ones slackened slightly, since I fitted the upper bracing bars fitted they remain tight  

[aerobod - near CYYC]

With the standard torque on the lower diff bolts, I've lost 2 in the past on the track (2 separate occasions), even though they were at the correct torque before the track day.

I now have a higher torque (100Nm), Schnorr washers and blue Loctite on them, no slackening off since.

[Jonathan Kay]

From another thread:

"Car back to have Diff rebuilt i will let you no if that was the problem"

[RAZA]

Picked car up after 2 weeks at CC it still has the same clonking sound very annoying 

[ScottR400D]

There's a surprise......

[edo]

Mine does a little bit of a clonk when I come off and back on the gas at low speeds. Mine is an S without the crap chocolate LSD.

Williams just gave it a very thorough check over and deemed that TADTS and mine was actually one of the better ones. 

[Andy135]

#15, so what did they do to the car during those 2 weeks?

[Nigel B]

#17   I had that issue with my old (live axle) Seven. In my case, it was caused by driveshaft splines that were a bit loose in the diff. 

My current car doesn't exhibit any clonking at all when you come off & on the throttle at low speeds, so I don't think it's a case of TADTS.

[RAZA]

They sent diff to R@R they said nothing wrong with diff witch takes 2 weeks there and back they are now saying  they are using the wrong oil in the diff    

[John Vine]

#20 It's unclear to me who the various "they"s refer to. 

Parsing:  CC sent the diff to R&R.  R&R said nothing wrong.  But who are the "they"s in the final sentence?  CC? R&R?

Is there a warranty involved here?

JV

[ScottR400D]

I would guess RR are saying CC are using the wrong oil. RR will push there heavily modified oil which hides some symptoms in the Titan. 

[Geoff Brown]

Is the diff fitted with a TITAN LSU ? After eliminating everything else then yes TADTS because of the chocolate tea pot LSU. The 'right oil' will help but only in a limited manner.

All I can say is, oh dear !!