Ok I am really confused,

ZF box a thud slight usually when slowing down and then at the change up from

First to second gear doesn't happen regularly, so the dilema is carry on and hope it stays

Like it is or do a flush out but other members say don't do the flush out as it will accelerate the

Problem and immenent failure of ZF box,

Any thoughts.

Sal RANGE ROVER OVERFINCHED 4.2 S/C
FRONT BUMPER O/F
REAR BUMPER. O/F
BOOT SPOILER O/F
22" ALLOYS. O/F
STAINLESS STEEL EXHAUST O/F
CARBON FIBRE WING MIRRORS & A PILLARS & CENTRE CONSOLE

@Mikeyjd - tough call. 100k miles... As I said, I've heard of people doing a fluid change - and that only seemed to accelerate the demise of the gearbox. You do have a pressure related problem, but as it is a leak down issue I don't know if a fluid change will do much for you. And the new detergents etc in new fluid may actually cause the quick demise I mentioned above.
You can ask RRPhil (pm). While he does more ZF he recently tore down a 5L40E out of curiosity. He has much more hands-on experience than I with auto-boxes.

Whatever you decide on, get rid of any paranoia. This will ruin the otherwise pleasurable RR experience
And if and when you have the box rebuilt, make sure you get the Sonnax bits installed in the valve body.

ebajema wrote:

@ Steve MFr, don't you hate it that a manufacturer tries to save a few dollars on a pretty expensive piece of machinery (not just the gearbox but also the car) causing major money and a long term reputation issue. I can't believe that this won't have a negative impact on the use of GM gearboxes in new model cars.

GM autoboxes had a reputation of being pretty "sturdy" (My GMC with 300,000 plus miles for example and many older GM models that would do hundreds of thousands of miles without issues).

In fact I do notice more and more cars (even GM cars) are fitting ZF gearboxes. Lets hope they don't make the same mistake.

and @ Simes

To you both: YES! This is exactly what happened here. The softer alloy was most likely used to save time and money on machining the valve body casting. And BMW canceled the follow-up contract with GM Powertrain for a 6 speed gearbox (there are articles if you ggogle). And GM Powertrain sold the Strasbourg plant where the 5L40/5L50 were built. This was in liquidation for a while but I think they are operational in some form again.

One of the problems we are faced with today: short term (shareholder value) thinking. 
RRC 2Dr, RRC 4Dr,
P38, and 2 L322s
(wife thinks I'm nuts - prob right, too)

Hi Steve,

And thank you, I did pm RRPHIL, who incedently lives in my town,

Said I should flush out the gear box, change the oil,

Sal RANGE ROVER OVERFINCHED 4.2 S/C
FRONT BUMPER O/F
REAR BUMPER. O/F
BOOT SPOILER O/F
22" ALLOYS. O/F
STAINLESS STEEL EXHAUST O/F
CARBON FIBRE WING MIRRORS & A PILLARS & CENTRE CONSOLE

There you go then, apart from the manufacturers troubleshooting guide recommending a fluid change (found it somewhere on the D3 site, but now for the life of me I can't relocate it ), the one forum guy who really knows gearboxes confirms, get the oil changed.

I mean for heavens sake, the gearbox is just another mechanical component of the car, except it's the most crucial to the drive of the car, and it's under enormous strain a lot of the time. Why would you assume that it will function OK with old oil, possibly burnt, and full of crud, when you know that it will then not be able to perform it's function as a lubricant?

Rant over!

Bottom line, despite the 'sealed for life' claim, nobody now says that's beyond 100k, and it can be much less in certain conditions. Nobody forces you to change your engine oil either!  2012 SDV8 Vogue SE

In the particular case of the ZF (6-speed) 6HP26 transmission the 2-1 rollout shift ‘thump’ is extremely well known and widely documented on forums as it been a feature on Jaguar (where it’s generally known as ‘the lurch’) and BMW (where it’s generally know as ‘the tranny slam’) vehicles which were fitted with this transmission 3 years before it appeared in the L322.

It appears not to be a ‘life-threatening’ condition for the transmission (more an annoyance) and the two pieces of advice to eliminate it are invariably to a) change the fluid and b) get the dealer to perform an ECU software update up to the latest spec. This was the early advice from Land Rover too.

However, Cam-Tech-Craig has reported on here http://www.fullfatrr.com/forum/post111623.html#111623 that the dealers have (recently?) been sent a warning from Land Rover now telling them not to change the fluid as this can cause ‘preload issues from the transfer box’. I wasn’t aware of this when I recommended salb to change his fluid and I’m therefore very curious to know more about this and I’m hoping that Craig can provide us with some more detailed information?

Phil

Problem is not Salb, it's me.

i've done the change, and the double flush, and it only accentuated the problem. So, i'm now getting budgets to get a new box or a ZF repair.

Damn it....

I did a triple flush on my box and everything is fine.

I do wonder if those who have done an ATF flush and then found problems already had problems before the flush was done