Clunking rear

[davidbolam]

Hi there,

 

My 1996 De Dion with LSD makes a clunking noise when warm.

 

mainly if I'm in traffic on and off the throttle.

 

I was told by Millwood the day after I bought this that it was normal due to no soundproofing etc. and the diff being really close.

 

Does this sound right?

 

Everything else seems tight and not loose

 

thanks

 

David

[MADMALC]

I would agree that it is normal. In traffic I found it easiest to dip the clutch and coast where possible.

[JNC]

If you aren't going to race it and use it for normal fast road remove the LSD and fit an open diff it's noise less ! I hate the banging diff it is not nice . Keep the LSD to sell with the car when you pass it on.

[SM25T]

Maybe too much play (backlash) in diff ? Or UJs in propshaft ? Get them checked.

[Silver Machine]

My 1997 k Supersport with LSD has always sounded like that. Had it all checked years ago and it still sounds sounds like that. Think that most LSD's when used on the road in a car where you almost sit on top of the diff may sound that way.

[Toby S]

My 1993 1400 supersport with LSD clunks - sounds pretty normal.-  one of the downsides of LSD, although brilliant power slides is the bonus - pays your money and takes your choice

 

[stan]

Clunk noise is a free option. My previous one did it always for years and now the same with my brand new one they gave you the right explanation no sound proofing, the diff is close to you and a diff must have some bakslash inducing this normal clunk noise.  

[Geoff Brown]

My R400D BMW LSD has clunked since new.

I have been tinkering with different LSD oils over a period of three years & during this winter service replaced the current oil with Castrol Syntrax 75w/140.

The car has been on the road twice this past week & at length to get really hot & I must say that the new oil has lessened the noise but not totally eliminated it. The Castrol oil supposedly has good shock elimination properties so presumable that helps as well.

[John Vine]

Castrol Syntrax 70w/140

That's interesting, Geoff.  Do you also use an LSD additive or does this oil do the whole business?

JV

[7 wonders of the world]

The plate LSD will not cause a clunk in drive / overrun if set correctly, this is far more likley to be excessive backlash as many were build incorrectly, or transmission shunt with laygear noise.

Plate LSD's can 'chatter' at slow speed with lock on ie forcing a difference in road wheel speed, however this is easily overcome by using the correct oil. Original CC supplied ZF units did chatter more as they were built using excessive preload - ie the same as uses in a road car ! circa 65 lb/ft.

If you want a correctly built, silent final drive speak with Steve at SP Components