Hi Folks,
Really was hoping I wouldn't have a problem so soon!!! Anyway, towing my caravan today, (good test for it just 2 days after buying), after about 30 miles, the gearbox suddenly changed down to 3rd and would not change back up. This happened at 50 mph and slowing down to about 35mph it changed down to 2nd. It would go back into 3rd but only after booting to about 4,000 rpm. The only way to clear it was to switch off and restart after 2-3 mins. I would then drive another 10 miles and it happens again. On my 80 mile journey this happened about 6 times. It is going back to the garage but I've yet to go home. It was as if it was in manual - but wasn't. Trying in manual didn't help.
Any ideas would be welcome.

Regards

Lenb Current: 2004 Vogue 4.4 V8 - 2004 Discovery 2
Previous: 2000 P38 DHSE - 1995 P38 DT Man - 1990 3.9 SE Classic, 1980 3.5 Classic 2dr

That is a protective mode for when it is running too hot. Some sort of cooling issue I'm afraid.

MC

I did wonder! And it does smell hot even though temp gauge Normal. No error showing on message centre and also it does 'judder' as though going over a grid occasionally. Current: 2004 Vogue 4.4 V8 - 2004 Discovery 2
Previous: 2000 P38 DHSE - 1995 P38 DT Man - 1990 3.9 SE Classic, 1980 3.5 Classic 2dr

I may be talking out of my ar5e but could be a gearbox intercooler, colleague with an X5 had that same issue

It's the gearbox temperature rather than the coolant temperature so coolant may well appear as normal on the gauge. When the gearbox detects over temperature it will hold onto higher revs in each gear in order to pump more oil through the cooling system to aid cooling.
It could be an issue with the normal coolant system though as it uses the coolant in a gearbox oil cooler as a heat exchanger, the bottom 6 or so cores of the radiator supply the oil cooler and if they get clogged/silted up then oil cooling will be affected.
Likewise the oil cooler itself could also be clogged up.
Cattle grid like judder below about 55mph is an indication of a worn lock up clutch in the Torque Convertor.

Mine did both of those things.  I ended up spending about £1800 on a full rebuild.


MC

Had similar problem last year when towing - changed the gear box filter and replaced fluids and also put a new radiator in her, mine has done over 150k on the clock - did same journey this year with caravan and no issues at all. Did a 300 mile round trip this week with a car transporter and VW Golf on it - towed it brilliantly.

Kiter
That sounds a bit more promising! I have an 80 mile journey home on Monday so will have to take my time. It's going back to the garage I bought it from as soon as I get back. I'll show him these posts. He seems a decent guy so hopefully it'll get sorted. (Got an even longer journey Oct with caravan so it had better get sorted!!!) Current: 2004 Vogue 4.4 V8 - 2004 Discovery 2
Previous: 2000 P38 DHSE - 1995 P38 DT Man - 1990 3.9 SE Classic, 1980 3.5 Classic 2dr

Make sure you demonstrate the cattle grid issue. It is a gearbox out job.

MC

my previous owner had a full gearbox rebuild, as was (gearbox) overheating and had done the little cooling rad at the front under the water rad already, it turned out (after rebuild,) to be the fluid pipe to (or) from the cooler was partially blocked, and required replacement. the rubber hose can collapse internally, causing a block. that was after £2500 gearbox work. you could disconnect/remove these and blow (mouth) air through them? (with clean tubing attached)

first thing to do, Is a fluid/filter change though.
the main reason I bought my 2002 v8 was that it had already had the gearbox done, as its one of those top 10 things to watch for, and sort of the hardest to do cheaply.

I did ask the dealer if he had done an oil change on the gearbox - to which his answer was "yes'. However I will get him to do it again. I also own a P38 so know how important this is!!
All this information is very helpful and much appreciated!! Thanks everyone!! Current: 2004 Vogue 4.4 V8 - 2004 Discovery 2
Previous: 2000 P38 DHSE - 1995 P38 DT Man - 1990 3.9 SE Classic, 1980 3.5 Classic 2dr

Gearbox oil and filter changed, codes read (nothing), flow test on oil cooler and ok. I will now do a tow test to see if it happens again.

However: The mechanic suggested that because I was towing at 50 mph (the legal limit on single carriageways) the gearbox would not lockup (which is 56mph) causing more heat. Does this mean I will always have this problem? Any thoughts on this appreciated. Current: 2004 Vogue 4.4 V8 - 2004 Discovery 2
Previous: 2000 P38 DHSE - 1995 P38 DT Man - 1990 3.9 SE Classic, 1980 3.5 Classic 2dr

I will probably regret saying this but........... since doing the filters/fluids and radiator on mine the problem has never re appeared - last trip with the tin tent was from Inverness to Oban so not a great road with lots of slowing down/pulling away again and dont think I ever got much over 50mph, no issues at all - tin tent is a twin axle hobby at probably just over 2 tonne with all the gear.

try reading up some more on how to 'hear' the torque converter 'lock-up'. (easier on a diesel for obvious reasons) it is sort of like, you just stopped resting your foot 'on the clutch' and you take it off, to feel the car, sort of heave forward, and pedal gives a bit more 'grunt' or 'feel' -revs decrease a little etc. you can overcome this problem at 50mph, by using manual mode with the gearbox. you can then, on single carriagways, hold 3rd gear, (or any forward gear) allowing 'lock-up' in say, 3rd at a slower speed. This will prevent premature wear on box, and give you drivabilty. you can pull it down a 'cog' with the gearstick, or drop it to 'D' at anytime, read the manual. i use this (manualmode) when driving with a trailer behind lorries on an incline.
basically at a certain speed, your gearbox stops 'slipping' and locks drive from engine to propshaft. if you kickdown, or labour engine, it will drop from lock-up to slipping/slushing again.

with some practice, you can get car to lock-up, and you resume driving very slightly slower, (still locked)

If the gearbox is fine, there is no reason why you should have to worry about the lock up....

It should tow it's maximum weight all day long at 30mph, or any other speed, with no issues

If it still does it then there is something wrong....

Did he use the correct gearbox oil as it's very important to use the correct stuff??

My money is on the rad, gearbox oil cooler and lines.... Pete

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