Despite hopeful preventative maintenance since 50k miles (annual draining 4L and replacing Texamatic 7045E transmission fluid + filter/sieve replacement) my gearbox lost all drive just before 120k miles.

It has now returned from rebuild (new TC plus replacement Sonnex valves) and I can recommend the repairers (no connection etc):
STA Aylesbury
www.staautogearbox.co.uk

They told me that they average at least one X5 or L322 TD6 a week for gearbox rebuilds...

The question for the panel is whether I should be thinking about the modified gearbox ECU (not sure if this is an IID tool reflash or a completely different ECU box) which reduces TC slippage, given that I now have new Sonnex valves and would like to reduce the TC wear in future?

I saw that there yesterday when I dropped my silver one off  Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!

Ah - they did mention that they had one coming in where the TC had been done already!

Do you mind giving me an idea on the cost for them to do the above work?

They quoted me £1800 + vat for a full rebuild, which bearing in mind they fit a fully recond valve block and TCC, it would appear to be a very keen price, That's what I paid 18 months ago and it didn't include the valve block... which has added to the early demise of my box , just wish I'd found STA before..... Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!

I note from their website that they have a Hydra-Test valve body test machine (with VBDaq data acquisition software), which is always a good sign. Anyone that invests £30k to ensure that they can thoroughly test the performance of their rebuilt valve body assemblies clearly cares about the quality of their re-manufactured transmissions (in my book, at least).

Phil

I paid STA £1700 + VAT (new TC & Sonnex valves fitted).

Phil - do you think that it's worth changing the gearbox ECU to reduce the TC slippage (from memory between 30-50mph), or should I just expect to replace the TC after another 80-100k miles?

Open torque converters are brilliant at isolating driveline torsional vibration – and particularly for diesels. The torque converter lock-up clutch ‘continuous slip’ mode is there for a good reason – to help isolate torsional vibration at lower engine speeds while still reducing converter slippage for fuel economy. Once the engine (vehicle) reaches higher speeds, locking the converter up solid is fine. I think therefore that you’d have to be very careful if you’re considering eliminating the ‘continuous slip’ mode, though admittedly the GM converter does at least have a torsional vibration damper – the ZF 5-speed doesn’t. Who is supplying and programming these ECUs? Can you get some reassurance that they have vehicles running for high mileages using these settings?

The latest automatic transmissions try to lock up the converter so early now (in the quest for fuel economy) that a large proportion of the space in the torque converter is taken up by increasingly complicated torsional vibration dampers – particularly for diesel models.



Phil

Thanks Phil - no assurances given from the modified ECU sellers I suspect (http://www.ecotuning-automatic.de) and I don't want additional vibration from the gearbox which now behaves properly:
- no vibration stopped at traffic lights in D (previously had to move to N to reduce vibration)
- much quieter and smoother than before at all speeds
- much smoother gear changes

Since I now have the Sonnex valves in the GM 5L40E, it was more a question of what I could do in order to avoid another TC rebuild in 80-100k miles (my annual transmission fluid partial changes may have possibly delayed the failure from 80 to 120k miles)?

From all the info I have gained in 2 to 2.5 yrs. I have come to the conclusion the GM 5L40E g/box is not up to the job.
I think land rover / bmw in their wisdom put in what was already available, even though the X5 has no transfer box, it still suffers the same fate as the ffrr. Its a real shame as the td6 is a good solid power unit, and I am no bmw lover, in fact the prospect of me owning something bmw was quite daunting.
I think you need to ask yourself, how long are you going to keep the car?
my past 2 g/boxes have lasted on average 65k each. I have no idea how they were driven or if they towed, I also have no idea what the last refurbishment consisted of. I do know now exactly what has been done to the g/box, so I'll just carry on driving it until I can get a later model car be it a ffrr or something else.
Glad you got yours sorted, and happy motoring.
Greg.

VaguelyVogue, unless your doing something drastic with your ffrr, like someone else on here ( not naming names, but a good looking chap, well my mummy thinks so ) a fully rebuilt box with the sonnex valve mods should return something near to the original gearboxes mileage. Especially with regular oil changes

The Eco tune does offer some fuel savings, but lets face it, it's a bloody big and heavy 4x4 shaped like a brick, the best way to improve the mpg is stick on the back of a lorry I'm looking at the Eco tune ECU purely to stop the partial lockup that has worn my box out very quickly through towing, and i'm not totally convinced that it will work in my application. Having said that, most who have fitted the system have given it a very favourable write up, but I'm not sure if they had the engine chipped too..

gregdav, what you say about the GM 5L40E gearbox is true, it really isn't up to the job, the M57 BMW engine outputs more torque that the box is designed for, and when you add in the extra weight that the Range Rover imposes on it somethings gotta give, usually your wallet I think that the GM box was sort of mated to the smaller 2.5 engine which is fine, and although BMW / Land Rover have detuned the engine, it's still more that the box can cope with over time. It is a real shame that BMW had already sold L/R when the L322 was pushed in to production with what now seams like 'that will do' attitude, rather than make it the best that we can... after all they did mate that engine to a ZF gearbox for the 7 series.... that to me suggests that they knew there was a problem with that power train combination and weight.... Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!

Totally agree mate. We are stuck with the GM box. For reference, my auto g/box specialist said, of the sonnex valve conversion, it wasn't worth the investment, in tools that is. As I'm not thinking of keeping the car for the next 80k or so, I didn't go for it.
I do hope it all works out for you mate, have been following your threads over the week's. RRPhil has given a great and detailed input on how these things work(hats off to you Phil) and gives us some idea of what we're up against.
All the best.

 Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!

GLOG update after 9 days driving:
- 8 days of short local journeys with expected fairly poor fuel economy (down to 20mpg) after the gearbox ECU was reset (still learning)
- 1 day of driving to France & back - huge improvement in both economy (28mpg on the motorway), smoothness and noise (SWMBO remarked how much quieter it was). 81p/litre for diesel in France also helped!

Very happy so far!