Hi folks,

I have an occasional transmission fault with my Feb 2009 L322 4.2 Supercharged, which results in the 'Money Bong!', LCD caption 'Transmission Fault - Limited Gears Only' and drive only in gears 1, 2 & 3. Once the car had been parked for a few hours and everything's cooled down, it drives normally with all gears 1-6 available. The first time it happened was July 2022 whilst towing a glider trailer on a French Autoroute at 80 mph (so quite high load through the transmission), and it also occurred yesterday after I had been 'booting it' a bit, so again quite high torque through the gearbox. It hadn't recurred in the intervening 11 months and about 2,000 miles of normal driving.

The logged fault codes are:

Faults: TCM-Transmission
P0730-00 (6D) Incorrect gear ratio
P0735-00 (ED) Gear 5 incorrect ratio (this was only for the July 2022 event)

Faults: ATCM-Terrain Response
U0401-94 (2 Invalid data received from engine control module/powertrain control module - Component failure - unexpected operation
U0402-94 (2 Invalid data received from transmission control module - Component failure - unexpected operation
U0416-94 (2 Invalid data received from vehicle dynamics module - Component failure - unexpected operation
U0403-94 (2 Invalid data received from transfer case control module - Component failure - unexpected operation

Having read previous posts, including RRPhil's wisdom on ZF transmissions, I think this means I have a fault either within the mechatronic unit solenoid(s) or, a bigger problem within the transmission itself, with the E-clutch which engages the epicyclic reduction module which gives you gears 4, 5 & 6.

I want to take the car to a good ZF transmission service centre for repair (I'm based near Alton, Hampshire). Googling brings up:

- Stephens Engineering in Ware, Hertfordshire
- Ashcroft Transmissions in Luton, Bedfordshire

Does anyone have any experience with these service centres, good or bad, and is there anywhere else I should be considering?

For info I had the transmission oil mega-flushed at 90,500 miles, car is currently on 100,200 miles.

Thanks, fanders
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2009 4.2 SC Buckingham Blue
2021 Hilux 2.4

Martin Hind at Dartford Transmissions and Autocare is who I would take it to and leave it with him for his expert analysis. Gone to a good home: 2011 4.4 TDV8 Vogue SE Buckingham Blue with Ivory and clear glass = "Rory"
2025MY Defender D350 90 in Silicon Silver on coils
1974 Series 3 Lightweight = "Millie"
Many, many other Landies over the years
My preferred specialist: www.glenrands.co.uk
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Thanks Rob ---------------------------------------
2009 4.2 SC Buckingham Blue
2021 Hilux 2.4

He is a gearbox pro. Gone to a good home: 2011 4.4 TDV8 Vogue SE Buckingham Blue with Ivory and clear glass = "Rory"
2025MY Defender D350 90 in Silicon Silver on coils
1974 Series 3 Lightweight = "Millie"
Many, many other Landies over the years
My preferred specialist: www.glenrands.co.uk
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I spoke to Dartford Transmissions but they can't even look at it until late next week, so it's going to Stephens Engineering in Ware on Thursday. I will report back!

fanders
 ---------------------------------------
2009 4.2 SC Buckingham Blue
2021 Hilux 2.4

Cool. Never heard of them but always good to get new places on my "list"  Gone to a good home: 2011 4.4 TDV8 Vogue SE Buckingham Blue with Ivory and clear glass = "Rory"
2025MY Defender D350 90 in Silicon Silver on coils
1974 Series 3 Lightweight = "Millie"
Many, many other Landies over the years
My preferred specialist: www.glenrands.co.uk
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It does sound like an E-clutch issue, most probably due to the rear stator bush being worn.

In 4th gear the E-clutch sees 72.6% of the transmission’s input torque, in 5th gear it’s 125.5% and in 6th it’s 100%, so the controller is most likely to detect slip across the E-clutch in 5th gear first.

Phil

Thanks for taking the time to reply RRPhil, your posts are always informative.

Jason at Stephens Engineering also said it was probably an E-clutch problem when I spoke to them this morning. Piggy bank now being raided!

Cheerio, fanders
 ---------------------------------------
2009 4.2 SC Buckingham Blue
2021 Hilux 2.4

Keep us posted and remember, "It's peak Range Rover"  Gone to a good home: 2011 4.4 TDV8 Vogue SE Buckingham Blue with Ivory and clear glass = "Rory"
2025MY Defender D350 90 in Silicon Silver on coils
1974 Series 3 Lightweight = "Millie"
Many, many other Landies over the years
My preferred specialist: www.glenrands.co.uk
--------------------------------------------------

Collected the Rangie from Stephens Engineering yesterday, all driving well on the way home.

I had a complete overhaul of the ZF 6HP26 gearbox including bench/flow testing of the mechatronic unit and replacement of all wear items internally. This work was done by a chap at Stephens who just does ZF boxes (over 40 years' experience on them), although I didn't meet him. The owner, Jason, also recommended replacing the transmission oil cooler (gearbox fluid to coolant liquid-liquid heat exchanger) as a preventative measure, which I agreed with. He said it was a bit of a sod to fit.

Costs:

£3,000 for the gearbox overhaul (ex-VAT)
£202.39 for the oil cooler (ex-VAT)
£150.00 labour to fit oil cooler (ex-VAT)
£4,033.67 all in, including VAT

Warranty on the overhauled gearbox is 12 months and 12,000 miles, whichever is first (which will be 12 months). He advised to check for leaks after a bit of driving, but as they're a long way from home for me I will do this rather than taking it back just for that. He also advises replacing the gearbox filter and the fluid lost in doing that every two years (I think they use Dextron gearbox oil rather than ZF Lifeguard 6). He's not a fan of megaflushing but I didn't have time to ask him about that further.

So all in all not cheap, but hopefully a good repair which will last a long time. It was interesting to see various ZF boxes in bits in their facility, the E-clutch is quite small considering the power and torque going through it. He had the car for a couple of days once it was all together to check the gearbox and allow it to go through its adaptation cycle, which he said was pretty quick (he said some boxes drive terribly to start with until the adaptations adjust properly).

I don't know how competitive they are on cost for this type of job, but I chose them on the basis that they've been around for a long time and are owner-operated (the owner is on the tools daily), and they have all the machining/test facilities in-house. I think I was probably better off taking the car to a gearbox specialist rather than to a local indy who would drop the box and ship it off somewhere like that anyway, as if there are any problems I would only be dealing with one company.

Hopefully I won't have to report further, and this write-up is useful.

Cheerio, fanders  ---------------------------------------
2009 4.2 SC Buckingham Blue
2021 Hilux 2.4

Sound like you paid the correct money for a top notch job, should outlive the rest of the Rangie now...  Pete
I now have permission from the boss to use Y.O.L.O. Enjoy life
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2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand Sold
2002 L322 Vogue 4.4 V8 Epson Green (Fatty Offroader) Sold
-Click for Project Fatty off roader-