KV6 (manual) Drivetrain "thud" when changing gear.

[Simon]

Following on from my noisey suspension thread and the article bought to my attention by laser558.

This is what happens and the normal circumstance it happens in:
1. Pull up at a junction and slow right down. Begin to coast a little but it's a flat road so I'm not pressing the brake and I'm not pressing the throttle.
2. I see the exit is clear but my speed dictates I select 1st gear.
3. I select first (still no throttle or brake pressed).
4. "THUD"
5. I drive away and everything seems fine.

The noise happens as I select first and only seems to happen when I'm not pressing either the brake or the accelerator.

The article laser558 has pointed out details changing the gearbox mount and was described as:
.... clonking from the engine bay when applying the throttle/backing off since about 30,000 miles. It sounded so bad that it felt like a large amount of backlash from within the gearbox was the cause.
Could the noise I am experiencing be one and the same problem?

[Phil]

Is it upon lifting the clutch up? If so, possible I guess, if it is when you push the stick into gear maybe something rubbing on the selectors on top of the box.

[Simon]

Only seems to occur when selecting first and mostly (but not always) from neutral.

You suggest the linkages rubbing on something? Would this manifest itself during other gear changes too?

I should note that the clutch is depressed during this occurrence... I don't notice it when I push the clutch then select first but only when I've depressed the clutch in anticipation of stopping (for example) but then decide I can go and hence select first to accelerate away. The noise happens (and can be felt) when I move the gear stick into first (as the gear engages).

[Phil]

Mine clunked upon engaging first, It was after I had the clutch master cylinder replaced and the muppets that fitted it under warranty hadn't routed the pipe properly and they had trapped coolant pipes the lot. The pipe was also resting on the selectors on top of the box.

[Simon]

So far as I know there has been no work on the clutch master cylinder nor on any of the gearbox selectors or the gearbox itself.

How would I go about checking that the selector cables (and all associated pipes) are routed correctly?

[Phil]

Best bet, is to have someone inside the car going through all the gears with you under the bonnet looking to see if anything is touching the levers on top of the box whilst they are moving, (Obviously when the car is stationary!;) ;) ) Have you not just recently fitted a new induction kit, I'm not sure of the routing on a V6 but is there anyway that it is resting on the selector levers?

[Simon]

Induction kit is a "home made" one and is basically the OEM airbox with major modifications ;) Therefore it is not resting on any of the gearbox parts etc. This noise has been occurring for sometime now but I only notice it in the circumstances described above so it's not always been at the forefront of my attention.

I will have to take things apart and have a look when I get chance.