Walenut, thanks, glad to hear it is just one of these things that happens and not diagnostic of impending doom! I had found that the cruise will cut out with a tap to the brake pedal, somehow just seems more natural to do it on the clutch and doesn’t flash the brake lights. I guess I also used to tap it off at the same time as taking up the speed with the accelerator pedal, rather than doing the brake tap, followed by the accelerator. 2005 D3 2.7 Auto
Previously:
2010 MY FL2 TD4e GS - Now gone at 199,500 miles, about 135,000 of them mine.
‘93 Defender 110 200TDi CSW
‘87 Defender 90 4 cyl Petrol
‘83 110 CSW V8 - best ever!
Range Rover 2-door V8 (not sure of year - 4-speed box and vacuum diff switch)
Series III SWB Diesel

If you think the revs drop but the car is pulling still, that is not clutch slip, that is a software glitch, I have had it on other makes with manual boxes, as you say it is intermittent, I wonder whether dropping out of cruise is due to software, you may be asking for an acceleration that the software considers a gear change is in order, a 60 to 70 mph speed change up hill using the increase speed button would cause an auto to drop a gear.
I had a Santa Fe manual that would drop out of cruise if the speed change was over 10mph using either the button or the accelerator, where Hyundai obtained the cruise/engine software who knows, but unlikely to have been an in house program, one of the first things I noticed with the Freely auto, you could change speed up to any increment without losing cruise, but would almost certainly drop a gear especially if using the button vigorously. my PC is slightly to the right of Genghis
2012 HSE SD4 In Orkney Grey now gone, best car ever.

Dartman, that’s an interesting thought.

As far as I can tell, the car has been serviced by good independents rather than a franchised dealer for most of its life (according to the LR website, the nearest dealer would have been 140 miles from the original owner!) so it may not have had a software refresh/update since new. Also being the Td4-e I wonder if it may be related to the eco mode - everything I’ve read suggests that eco mode is too clever for its own good, so I will try with that switched off for a while.

I will be replacing the battery fairly soon and I guess shorting out the battery leads for a while to reboot the ECU might be worth trying? Past experience suggests that rebooting tends to solve one problem and create two new problems, so I am slightly wary of doing this, but if I am replacing the battery, it makes sense to do it.

I can see logic in a steering wheel-mounted cruise button (as opposed to a stalk-mounted button or pedal) not accepting continued input to avoid asleep-at-the-wheel or “deadman” acceleration, but it seems to accept that input on the flat. 2005 D3 2.7 Auto
Previously:
2010 MY FL2 TD4e GS - Now gone at 199,500 miles, about 135,000 of them mine.
‘93 Defender 110 200TDi CSW
‘87 Defender 90 4 cyl Petrol
‘83 110 CSW V8 - best ever!
Range Rover 2-door V8 (not sure of year - 4-speed box and vacuum diff switch)
Series III SWB Diesel

Replaced the battery on mine last year, never rebooted it. I would just use it for a bit and see how it pans out.

Make sure you get the right battery, their gel in fibreglass (forgot the proper name) traditional batteries will cause problems. I have stop start. Be aware that it will take some time, for the ECU to recognise the new battery, particularly if you only do short journeys, for the stop start to start working again.

Just to throw something into the conversation. One of our FL2s had what we thought was a slipping clutch at about 50k miles. I spoke to the dealer service manager and he said that rev counter can be misleading in that there can sometimes be a slight delay between what the engine is doing and what the rev counter is displaying, this only needs to be about a second or so but it can give the impression of a slipping clutch. I was a bit skeptical but agreed to see how it went as the gear changes were smooth and the clutch seemed otherwise OK. We finally traded the car in at 80k miles without a clutch change so perhaps he was right. 3 x FL1 2 manual + 1 auto
5 x FL2 4 manual + 1 auto
Now Discovery Sport P250 MHEV SE

Unless I am mistaken I too think that a drop in revs cannot be a slipping clutch. Clutch slip would normally give a momentary rise in revs where the engine would be freed of the gearbox drag.

I had the same symptom - a slight juddering when powering down to overtake, and a slight drop in revs - but in third gear. It happened a few times over the space of a few days some time ago. That was at about 70,000 miles and I've since just broken 100,000 without a repeat of the issue, possibly save for one time a few months ago but frankly I'm still not sure whether I'd imagined it.

Have you changed any tyres recently?

The haldex system does some funny things, it can sense the axle revs and it does a restart every now and then if it thinks one axle (usually the rear) is going faster than the other (caused by larger or new tyres on the rear) if this is the case and not sorted, it can lead to haldex failure (mine did). Remember the haldex uses 4 wheel drive to pull away and low speed manoeuvring, then adjusts itself and runs predominantly front wheel drive unless it detects wheel slip

Mine was my fault, I put new tyres on the rear not the front causing the haldex to do restart every mile or so which gave a very slight shiver to the transmission (as if you lift off slightly) as the axles were doing different speeds due to the tyre diameters. The Haldex failed after a few months of this as I did not swap the new tyres to the front to cure problem. Expensive learning!!

Having said all that, it may be nothing to do with this at all, hope you find a cure.  MY2014 SD4 XS
Ipanema Sand

MY10 TD4-e GS Manual
Lago Grey Now retired after 8 trouble free years

Again, thanks for the above comments.

My understanding of the high gear clutch-slip issue that others have reported is that it initially shows as a slight over-revving before the clutch fully picks up the drive, and I am assuming that this is accompanied by a subsequent drop in revs as the engine takes the added strain and the over-revving stops.

Interesting about the tyres. The front tyres are getting near the limit and need replacing. The rear ones are much newer, so there could be a slight diameter issue. I hope to get the front ones replaced next week - I had one slightly interesting corner on a slushy road this week and definitely need better grip on the front!

A haldex service, or at least a fluid and filter change, is on my (growing) to-do list. At 80k it is bound to need it.

I tried to test the cruise issue uphill on a trunk road last night, but was foiled by a Discovery trundling up the hill at 45mph! 2005 D3 2.7 Auto
Previously:
2010 MY FL2 TD4e GS - Now gone at 199,500 miles, about 135,000 of them mine.
‘93 Defender 110 200TDi CSW
‘87 Defender 90 4 cyl Petrol
‘83 110 CSW V8 - best ever!
Range Rover 2-door V8 (not sure of year - 4-speed box and vacuum diff switch)
Series III SWB Diesel