Autobox fault - can anyone advise?

[Synchromesh]

So my 2000 S-type V8 has started making what I can best refined as a 'rattling' sound at idle and when accelerating. Sounds almost metallic, sort of like a very old diesel engine. Here's a youtube vid I made when I first started hearing it, it was noticeably worse when I drove it to the garage the next day:

https://www.youtube.com/watch?v=SLxqn6bMhPQ

Two mechanics there have advised that it's related to the gearbox, so it's been dropped off at a gearbox specialist. Hopefully they'll give me some sort of diagnosis on Monday. In the meantime, does anyone here have any suggestion as to what it might be?

[BE57 TOY]

I can't hear what you mean?

[Synchromesh]

BE57 TOY said:

I can't hear what you mean?

Recored on an iPhone so doesn't really capture the noise at idle properly, but you can definitely hear the noise during acceleration in the video

[tgr]

Crack in flywheel? Get it checked out quick in any case, reduce your driving to the absolute minimum to get the car to an auto box specialist

ETA how can anyone called synchromesh not know what's wrong with a gearbox?

[Synchromesh]

tgr said:

Crack in flywheel? Get it checked out quick in any case, reduce your driving to the absolute minimum to get the car to an auto box specialist

ETA how can anyone called synchromesh not know what's wrong with a gearbox?

It's sitting outside a specialist right now, just worrying me a bit so wanted to get some early opinion.

Hadn't realised the irony until you pointed that out

[tgr]

Nice one. With any luck you caught it in time

Let us know what the damage is (fault and cost)

[paintman]

Be interesting to know what the fault was.
Can I guess at a cracked flex plate?

[Synchromesh]

So the transmission specialists had it up on the ramps yesterday and said that the box is "unlikely" to be the source of the noise. They were reluctant to take the box out to investigate further which, given it would be in their commercial interest to do so, means they're probably being straight with me. That and the fact they said there was no oil showing on the dipstick - they had to top it up 5 litres meaning I've been running it almost dry! Silly boy I am, I know. I meant to get round to checking it but it was serviced a few hundred miles before I picked it up and there was no low oil light on the dash so didn't make it a priority. Looks like that mistake came back to bite me.

Anyway, likely engine damage?

[Aydena]

From that video to me it sounds like a big end knock?

[Synchromesh]

Aydena said:

From that video to me it sounds like a big end knock?

A couple of people have said that. Am I right in assuming that's an engine out job?

[Aydena]

It depends, I've done a couple which can be done in situ, others have had to have the engine pulled.

[GavinPearson]

It is big end knock. I have some advice, you can take it or leave it, but I have had the same thing happen to me.

1. Do not drive the car, at all. Tow it from now on.
2. At the workshop, if you have the engine suspended on a bar across the suspension turrets, the 2 crossmembers, anti roll bar and steering rack can be removed.
3. The sump can then be removed.
4. The big end bearings can be changed with the engine in the car.
5. Reassemble.

Use 15W40 oil.

Failure to attend to the problem immediately (next 100 miles) will result in a big end bearing spinning. It will be very expensive to fix.