Bit of a problem today

Car is a Diablo VT 1997

When driving in gear and I take my foot off the throttle there is a knocking noise (happens in any gear) - The knocking seems to come from somewhere under the gear stick (hard to tell) and can be also be felt vibrating through the gear stick. The knocking speed also increases / decreases with the speed the car is travelling at.

When driving in gear a keeping my foot on the throttle, ie. powering forwards, there is no knocking noise.

Anyone have any ideas what the noise could be?, anyone experienced anything similar?

Also, does anyone know the closest Lamborghini specialist to Newark, Notts. UK?. Closest i've found so far is Birmingham.

Brief update,

Just been out for a short drive so I can best describe the noise.

The knocking noise is also there if i just coast in neutral, the quantity of knocks reduces the lower the speed the car is going. It does however still go away if i accelerate.

To describe the sound as I visualise it ... it's like a bolt is loose on something, every time it rotates it taps on something. It's not massively loud, nor does it cause huge vibration. Also, as a guess I would say it's roughtly one knock per each wheel revoultion.

Hi

I don't have a Diablo (Countach QV instead) - But I did work for FMC as a NVH engineer for a number of years.... so I will try and help.

Have you checked the tyres for any stones/screws or even bolts in them? I know this sounds a bit way off - but you'd be surprised! So many NVH concerns have the "route cause" some way off from where you actually think the concern area may be!
Another concern area could be a drive/prop shaft joint.
How fast do you have to be going before you can first start to hear the tapping noise?

Best Regards

Ian

Trans mount?

Hi Ian,

Many thanks for the reply,

Just jacked it up, no bolts / stones / anything stuck in the tyres - all look OK.

Just been for another quick drive, the noise becomes apparent at 20mph. It may still be there below that speed, but not noticable.

From the sound inside the car when driving, and when hanging half out of the car while it's moving! ... the knocking seems to me to be anywhere around 2 feet in front of, or 2 feet behind, the gear stick. Which part that relates to underneath the car i don't know. Do you think from that it's more likely to be drive shaft related ?

Regards,
Dave

First i do not recommend you driving the car till you find the root cause as you might damage tranny/engine.
Second If the noise goes away with higher speed it could be your flywheel screws are loose i could be wrong but i did experince that when i had my Corvette.

I would have checked your CV joints. I had to take my drive shaft off to find the fault as I had a knocking noise as well. Just my 2 cents...

__________________
Cheers,

Bjoern

Many thanks for all the replies,

I had the car picked up and taken to a specialist 2 weeks ago - it's still sat there gathering dust are they are very busy 'apparently' to even look at it yet.

Lambo ownership is not looking very positive to me at the moment ... 3 days into ownership & it's gone for at least 6 weeks and i'm driving round in my 'spare' car ... a £300 wreck !

Cheer me up chaps, My old 355 never (and i mean never) broke down, 4 year ownership, rain, snow, hail anything ... started first time, never stopped, no noises, nothing went wrong. I know Diablos are in a slightly different league - but surely someone must have a reliable one to boost my confidence.

Finally a point to note about Lamborghini Birmingham. I tried to initially get my Diablo repaired there (my closest main dealer) - The lady on the phone said they did not have a lorry to collect the car. This is a main Lamborghini dealer who does not even have a suitable lorry to collect a Diablo. She advised me to drive it to them - I replied that with a serious knocking coming from the car this may not be a wise idea to which she replied that they could therefore not help. It amazed me ... I therefore went to a specialist over twice the distance away who collected the car within 5 hours.

Dave

Does it sound like a tin knocking... like a bean can or something rattleing around

Hi Chaps,

Firstly, thanks for all the advice on this and the other thread i started.

Bit of an update - The knocking noise turned out to be 90% due to a broken mounting on the front differential. The garage it's at have fixed that bit now, but, sadly the other 10% of the knocking is from somewhere within the gearbox apparently, probably all related to my difficulty to get into 3rd.

... so it's there still waiting for a slot for them to get started on an engine-out job.

I'll post any updates as & when i know more.