Pulled the caravan a couple of hundred miles last Thursday without any issues. Toured about for another couple of hundred miles on Friday and Saturday, no problems.

On Sunday morning, I had travelled only about twenty miles when I got my first ever significant warning on the dash - "bong".... Gearbox Overheat. There was then a resident yellow triangle on the display. Car only has 50k miles on the clock and also had a gearbox megaflush in the past 5k miles.

I have to admit to a slight nervousness, as I still had a caravan to drag home on Monday.

However, I soon found a suitable place to park and switch-off while we enjoyed the sunshine and the view for a wee while. I also clicked into this site whilst sitting there and found three old posts about the issue which didn't inspire much confidence. Talk of clogged oil filters and blocked main radiators, neither of which 'should' apply here....

Anyway, engine was turned back-on after fifteen minutes and all was well.

Fifty miles of single tracks and steep inlcines later, nothing.

Towed the caravan two-hundred miles home yesterday, nothing.

Just a glitch in the Matrix???  The older I get, the more I realise that people confuse wrinkles for wisdom

You had a megaflush, was the oil pan replaced? Christian.


Current Cars
2011 Range Rover Vogue SE
2020 BMW M4 Competition
2019 BMW X4

My RR Blog: www.facebook.com/L322Project
or
https://www.fullfatrr.com/forum/topic61540.html

No ideas! Will need to ask 'Mikey' (MMP4x4), as he's the one that did it.

What's the significance of replacing the oil pan? The older I get, the more I realise that people confuse wrinkles for wisdom

The oil pan has swarf magnets and a built in oil filter.

It's supposed to be changed when the oil is changed. Christian.


Current Cars
2011 Range Rover Vogue SE
2020 BMW M4 Competition
2019 BMW X4

My RR Blog: www.facebook.com/L322Project
or
https://www.fullfatrr.com/forum/topic61540.html

As I understand it, the filter was changed at the same time as the megaflush. The older I get, the more I realise that people confuse wrinkles for wisdom

Any idea how the process works then?

I'm trying to work out how the flush does not push old oil through the new filter or vice versa. Christian.


Current Cars
2011 Range Rover Vogue SE
2020 BMW M4 Competition
2019 BMW X4

My RR Blog: www.facebook.com/L322Project
or
https://www.fullfatrr.com/forum/topic61540.html

It probably does push old oil through the new filter but highly unlikely it's going to be moving anything that hasn't been caught in the old filter or magnets. A gearbox oil change is mainly about changing oil that has worn out due to heat and age rather than contamination. On a gearbox with only 50k miles there should be nothing in there apart from old oil. 2012 TDV8 Vogue (L322)

I had to have my transmission cooler valves replaced as they had seized.
I went to Dartford Transmissions for my mega flush but couldn’t do the work because of it. I had it replaced along with a new cooler whilst it was in a few weeks later, and then flushed. (Incidental they DO replace the pan and filter as part of their mega flush)

So, you may have a gearbox that is struggling to keep cool when towing?
It’s probably worth getting it checked as an overheating gearbox is not good and will cause problems with the components and shortens the oil life too. Currently driving: 2012 L322 SE Overfinch 4.4 tdv8

Past rides:
2014 Audi Q7 3.0d (good riddance)
2010 L322 Autobiography 5.0 Supercharged
2011 L320 HSE 3.0 sdv6
2014 Jaguar XF-RS 5.0 supercharged
2007 BMW 535D
2005 Mini Cooper S

https://www.fullfatrr.com/forum/topic59478.html

200+ miles of towing without issue yesterday. Fifteen miles of normal A-road driving on Sunday and it threw a spurious alert which hasn't happened again.  The older I get, the more I realise that people confuse wrinkles for wisdom

There is a transmission oil temperature sensor in the Mechatronic pack, there is also a secondary transmission temperature calculation carried out based upon calculated load.
If the sensor fails, then a default value is set (doesn't sound like it in your case) and a DTC is logged.
Given your continued event-free driving, it sounds like the sensor is giving false values in specific conditions - it's also possible that if this occurred on an extended hill climb, gravity may have had a hand in setting a false positive.

Check your transmission oil level, if all OK and no DTC set for the temperature sensor failing,then it's probably just a combination of circumstances rather than a defect.

ETA - the 'overheat' message can also be triggered by an engine high temperature condition, is the coolant level OK? does the engine cooling fan / aircon work OK?

You'll need to be able to read the full DTC, not just the first five (Pxxxx) to reliably diagnose the cause of any DTC's set.

If you have an IID tool, you can set it to data log transmission oil temperature.

In my head, I'd be running through the following order:

1. Monitor. Sometimes these spurious errors occur due to low battery, ECUs not starting up / resetting correctly and it could simply be a random error never to be seen again
2. Sensor - is the sensor behaving correctly?
3. Check transmission fluid level. If there's not enough in the transmission or it wasn't properly filled as per the ZF procedure, a transmission will be prone to overheat. Topping up is simple and a litre bottle of ZF Lifeguard doesn't cost much. I'd do the run-in procedure again, to ensure it's correctly filled
4. If all of the above have been done, investigate the transmission oil cooler (also bear in mind it could have been airlocked) 2015 Range Rover Autobiography 4.4 SDV8

Thanks for the insights chaps!

Everything about the engine / box is 'right'. Megaflush 5k miles ago. Oil Cooler gaskets/O-Rings done at New Year. Engine oil/filter done 600 miles ago. No loss of oil or coolant etc. New AGM battery in the past few months. Engine temp steady as a rock. Aircon working fine. No behaviour out of the norm, other than this one spurious claim from a few days and 250+ miles ago.

I don't have an IID tool, simply because I've managed for 13 years of L322 ownership without one!

The spurious claim occurred as I was on cruise at 50mph and the car was running away (60mph) down a hill towards a 30-zone. I pulled the left paddle a few times to drop some cogs and that's when it happened - Bong!!

The extended hill climbs (on single track roads in 25deg heat) came later in the day and were acheived without issue.

I'm tempted to ignore this one-off event and chalk it up to the car having a sneeze. Trouble is, I'm now driving every time wondering if it will happen again.  The older I get, the more I realise that people confuse wrinkles for wisdom

Maybe best to use the brakes for slowing down on a hill while towing as that's a lot of kinetic energy to dissipate in the gearbox. 2012 TDV8 Vogue (L322)

I wasn't towing when it happened - just out for a Sunday drive!  The older I get, the more I realise that people confuse wrinkles for wisdom