This is probably one for RRPhill, I've had quite a few autos in the past, although I'm no expert I basically understand how they work. Now, the issue I have sounds like the common tc fault but I am struggling to understand what's physically happening inside the tc when these symptoms appear? I have the vibration at 1800rpm and the intermittent grumble both of which happen when in a higher gear, it's almost as if it's labouring? So what is happening when it does this? From what I can find out its when the friction material is gone and the debris is floating around the valve block? But how would that cause the noise and stuttering and why only at this rpm? In my circumstance I have no slippage in any gear, no thudding into gear, no harsh down changes when pulling up, these all seem to be hand in hand with the tc problems usually?
I have had the RR about 5 weeks now, I've dropped the fluid twice which was dark but no glitter, there's an invoice for a gearbox change about 18 months ago, I've called the company and at the cost it was he said the tc would have also been changed, I'm beginning to think it was a box swap only, I'm going to flush the fluid completely this week and drop in a new filter, I will update this when I do so, fingers crossed it will prolong my problem for a while, but ultimately I think the tc needs changing, if I keep the fluid changed regurely I may save the box......

Jay,

Have you downloaded a copy of RAVE so you can go through the workshop manuals and diagrams etc? This might help with your getting to know the car process too.

It's in the Wiki section:

http://www.fullfatrr.com/wiki/RAVE_downloads Discovery 4 HSE
1998 110 TUM HS FFR Hard Top XD WOLF
1982 Series 3 Hard Top

*Gone:L462 D5 HSE LUX, L663 Defender 110 HSE, Discovery 3 HSE, 2014MY Range Rover Sport 5.0 Supercharged AB Dynamic; L405 Exec Vogue SE 4.4, 5.0 Supercharged Autobiography, Defender TDCi XS CSW, Defender TD5 HT, Vogue SE TDV8, Vogue TD6, RRSport SC 4.2V8, Classic 3.9 Vogue Auto, Land Rover Series 3 SWB

Not sure if I'm being daft but the download seems very hard to get understand? All the folders and pages are just letters and numbers? Nothing seems to relate to what it should be?

Try this:

http://www.landroverresource.com/rave.zip Discovery 4 HSE
1998 110 TUM HS FFR Hard Top XD WOLF
1982 Series 3 Hard Top

*Gone:L462 D5 HSE LUX, L663 Defender 110 HSE, Discovery 3 HSE, 2014MY Range Rover Sport 5.0 Supercharged AB Dynamic; L405 Exec Vogue SE 4.4, 5.0 Supercharged Autobiography, Defender TDCi XS CSW, Defender TD5 HT, Vogue SE TDV8, Vogue TD6, RRSport SC 4.2V8, Classic 3.9 Vogue Auto, Land Rover Series 3 SWB