I had some pleasant and unpleasant experiences with GM auto boxes. The first and pleasant one, was resolved by flushing the box with diesel. Old trick recommended by one of our chief engineers (one of the best in the business actually) and it worked fine. The old ATF started gunking like nobodies business and the diesel cleaned/flushed the gunk out. The gunk was preventing the valves from working properly, they stuck in place, halfway etc. causing the box to start acting erratic. After that two full flushes diesel and then two flushes with ATF it ran like clockwork for a long time, until I sold a few years later.

The second on a GMC van (same box) was less successful but in defense of the box, it was likely to have done at least 300,000 miles or more. It failed spectacularly on a highway in Holland although I did crawl to my destination in first gear. Complete reconditioned replacement box solved that.

I suggest that you take it to an experienced specialist and let them look at it first. Then take the safest way. In the case of not enough ATF changes / ATF degradation, the diesel trick could work but if the box is just ready for its refurbishment the diesel trick does not work at all (it didn't help me on the GMC, that's for sure). MY 2010 5.0 SC Galway green and sand interior!!
Have the Faultmate MSV2 Extreme to be tinkering with the settings etc. !!

Can't help you with where to go, but as Steve said above, when you go to get it fixed, ask around to see who will do the Sonnax valve body upgrade - well worth it. I had some stronger frictions put in mine as well - they are available from a local car over here - the Holden (GM) Commodore. The torque converter will be slowly disintergrating, which will probably stuff the pump up as well. If the pump housing is damaged, it will need machining, and as it is part of the trannie case, there are only a few people around that can do this properly - tolerances are VERY tight here, and if not done properly, this can lead to premature pump failure - mine was done wrong first time and lasted a week... All done properly now by someone else, and thankfully paid for by the first guy...

Do your homework, and only take it to someone who knows these particular boxes, not just Joe Blogs Autos...

Autolock in Crewe did mine and they always seem to have a range rover in ( which is a worry )
But not to far for you
Budget about £2K!! Mine was a blue one!

Ebajema, the problem with the GM5L40E installed behind the TD6 motor is that the valve body was cast using a slightly softer alloy. This seems to be a problem particular to this transmission and has nothing to do with the transmission fluid. The valve bores wear and the operating pressures become too low.

I would change the fluid in a box that's in good shape or been rebuilt at 60-80k mile intervals. I have heard, though, several reports of people changing the fluid in cases like this and it seemed to accelerate the problem. 
RRC 2Dr, RRC 4Dr,
P38, and 2 L322s
(wife thinks I'm nuts - prob right, too)

Andy3681 wrote:

Autolock in Crewe did mine and they always seem to have a range rover in ( which is a worry )
But not to far for you
Budget about £2K!!

The vehicles at work have oil samples sent away for analysis, gives them a heads up for any problems brewing.
Maybe a specialist could do the same.

Mike
Contact RRPhil he's an expert on the GM and ZF box's. He's in Preston so not to far away and might know who to talk to or even help you out.
Rob [img]http://www.fuelly.com/driver/rob2529/range-rover[img/]
04, 4.4V8, Vogue Oslo Blue with LPG.
"You can sleep in your car, BUT you can't race your house!!!!"

If something can't be fixed with a hammer....... You have yourself an electrical fault!

It's been a while since I started this thread, so here's my latest update.

I was contemplating where to go as I was convinced my gearbox was on its way out. The occasional juddering had become a bit more regular and so I thought I would try a couple of places to get a few different opinions. Anyway, first call was to an auto box place near Chester. I turned up without an appointment and sat in the waiting room for a while. Eventually one of their guys told me he had checked out the car on the computer with nothing conclusive, so he took me for a drive, the juddering was worse than ever, but he dropped the car into neutral whilst it was being driven and the juddering was still there, he said this would suggest it wasn't gear related. He also mentioned the lazy starting in the morning could be caused by excess fluid draining (or something like that)

We then had a chat about possible problems and I told him I would go and think about it. (my intention was to try somewhere else for a second opinion). On my way home I noticed a squeeling from the rear near side brake. On checking I found that the pads were badly worn and the calliper seemed to have seized. A couple of days later, new callipers and pads fitted and the car ran great. No more squeeling and no more juddering either. Seems like maybe the seized calliper was causing the juddering.

Since then I have done a few hundred miles with no sign of juddering at all. Gear changes are smooth and quiet. The car is still a bit lazy when it has been standing for a day until it has been running for a minute, then it pulls away smoothly and runs perfectly all day.

So, my dilemma now. do I just carry on driving the car or what? What is causing the lazy morning starting? Maybe when I had the fluid changed a few months back they didn't use the correct fluid or didn't fill it properly. Should I change the fluid myself or what? Any thoughts or comments please. No longer FF owner but still interested. Present car Jaguar XE
............................................

Previous car Td6 SE
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Previous LR- Disco 300TDi Auto

Mikeyjd wrote:

So, my dilemma now. do I just carry on driving the car or what? What is causing the lazy morning starting? Maybe when I had the fluid changed a few months back they didn't use the correct fluid or didn't fill it properly. Should I change the fluid myself or what? Any thoughts or comments please.

Are you sure the filter was changed? If it was then it won't do any harm to change the sump oil and refill. Had the incorrect fluid been filled into your box I doubt it would still be going now, the seals are rather sensitive and as each oil type has different properties the incorrect fluid would soon cause lots of problems. If I were you I would keep driving it and see how it goes

@ 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. MY 2010 5.0 SC Galway green and sand interior!!
Have the Faultmate MSV2 Extreme to be tinkering with the settings etc. !!

The trouble is that it's not as simple as the manufacturer tryingto save a few dollars (or pounds) on the manufacturing - it's really our fault as consumers. We want something that's perfect and will last forever, but we always want it as cheaply as possible.

In the case of the GM box the story will go like this (been there many times):

LR involve suppliers during design of vehicle and ask for sample items and prices for production.
Supplier works with his suppliers to do the same thing
Supplier hand builds a few samples (maybe 100)
LR (or $carcompany) Likes it - selects one or two suppliers for production
3 months into production, real engineers are now off on new project, production engineers and buyers tell suppliers if they want to keep supplying they need to get 10% out of the costs today, then 10% per year for the life of the contract. Supllier should tell them to get stuffed - but he doesn't as he's invested millions in the production line etc. So he gets onto his suppliers and says the same - 10% then 10% per year...

They are all in the same boat, so they start looking as saving money - well - we can use less pressure in the high pressure aluminium die casting process and change the alloy slightly so that the part is a little lighter and a little cheaper etc etc... Quality goes out of the window.

Buyers don't care really - as most first time buyers are fleet managers who want the car to last 70,000 miles - ideally without servicing.Even private individuals who can afford to buy new, rarely keep them that long. Good example, many years ago I was at Jag - I asked why they rotted away after five years - the answer - no-one who can afford a new Jag would be seen dead in one five years old, so why bother rustproofing it?

So, with most cars, as long as it looks nice for 3 years, needs little servicing for 70,000 miles (at the expense of longer term viability) it's fine.

Sad .......but true

Mikeyjd wrote:

I had my fluid and filter changed a few thousand miles ago after reading all the woes on here. Don't know if it delayed or exacerbated the problem though.
.

Well I didn't have the oil changed on my gearbox, and it's gone at 85k. I really don't think that changing old burnt oil which is full of crap, for fresh new oil, can 'cause' gearbox failure. If the gearbox is so far gone that it's only the crud and debris in the oil which is holding it together, I guess it might precipitate failure a bit quicker.

But I'd say if you don't change the oil, you're on borrowed time. Just my humble opinion though (having had to have a 5HP24 gearbox rebuilt in a BMW too!). Range Rover-less at the moment - Pining!

crud and debris sitting on the case broke down by the additives in new oil ? 2004 black Vogue TD6