Let me start this story by making it clear that I'm no gearbox expert! If we get a customer car with a gearbox issue, it gets diagnosed and we would then have the gearbox rebuild or replaced...

So, I have acquired a 2006 4.4 AJ V8 with a duff ZF 6SP gearbox! I asked everyone with any experience and they all said "there are many many variants! You'll never get the wrong variant to work! it has to be a matching 4.4 gearbox. Definitely NOT a 4.2SC variant" I couldn't/wouldn't justify spending the £2850 trade price for a new gearbox as the car has nearly 200k on the clock...

So, I duly found a 4.2 sport being broken with only 82000 miles and the breakers agreed on a price with the matching torque converter which was delivered a couple of days later...

Out came the duff unit which was full of Aluminium swarf! So I'm guessing the torque converter had self-destructed! In went the donor box and TC and it immediately went into limp mode BUT drove forward & backwards so i was making progress and then it dawned on me, so i took the mechatronics unit out and stripped it down and changed the black electrics part? valve block electronics??? Then voila! Gearbox working again! After removing the cooler & pipes and cleaning out everything, servicing it with a new filter/sump and new fluid. I then took it for a 40-mile test run and she's perfect!

So, IMHO the 6SP ZF mechanical parts are only told what to do by the TCU and the electronics pack/valve block.

Hope this helps someone in the future?

RRPhil, if you do read this thread? Id love to know your thoughts sir?

Craig, That's really interesting & reassuring to know.

Pleasing to read, i've a juddery tc at the minute and my local garage suggested that I wait for the gearbox to go and get it changed then. My 3.6TDV8 is just over 150K and like Craig, there's no way I could justify putting a new gearbox in it so knowing there's an alternative is great - cheers!

excellent detective work

. Cheers, Greg
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2011 Vogue SE 4.4 with lots of toys in Stornaway

Thank you

Well, were a couple of hundred miles down and all is VERY WELL

 l=Oo\________/oO=l l:OolΞΞΞΞΞΞΞloO:l

Current
RANGE ROVER Vogue 4.4L SDV8 - 2013 - Indus Silver, on Almond.
RANGE ROVER Vogue 4.4L V8 - 2002 - ex-2003 G4 Challenge Event Vehicle, Stage 3: Australia
RANGE ROVER HSE 4.4L V8 - 2004 - one-of-one Overfinch
RANGE ROVER P38a 4.0L V8 - 1999 - ex-2000 TReK Event Vehicle: South Africa

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well done