XSeries-forum

Hi there.  Recently towed my boat (600-700kg) back from Bridport to my home town of WSM. 

On the way back the car wouldn't let me go into 5th, and sometimes 4th, and even on the motorway when I was on the flat it often wouldn't let me go into 5th.  I think when I stopped, turned it off and started again it cured it temporarily but came back pretty soon.  Even in manual mode it wouldn't go to 5th, sometimes 4th either. 

The drive does involve some pretty decent size hills so I guess this could have contributed to the problem.  A friend said heat in the gearbox could be a problem.

Once the boat had been put back into storage and the car had been given a decent (30-45 min) break, it seemed to be ok.  This does lend itself to be a heat issue I realise. 

Any suggestions chaps and chapesses?

Happy to provide more info but thanks in anticipation for any info that may help.

Ta.

I wouldn't have thought 6oo or even 700 kg would even be noticeable on the back of a 4.6, litre X5.
I had over 1.5 tonne on a plant trailer today at work and it went over the Pennines on the M62 in top gear in a transit van.
We used to tow a horse trailer with a shogun, 2.8 and a Kia sorento, grossing 2.3 tonnes with little effort.

That weight in the back should have been no issue at all as said above.  I thought the max was about 2.4T?

Sounds like a cooling issue (blocked pipes or crudded up oil cooler) with the transmission cooler.  I think that if the box gets too hot then it goes into 'Sport' mode and holds the revs to the red line and it may ignore any manual inputs.

Might be worth getting the level and oil 'colour' checked to see if it's OK.  I can't remember where the cooler rad is but it may be below the main rad.

Richard

I did think that.  When I first started towing it seemed to pull beautifully then as I got further into the journey issues-a-plenty. 

I'll dig about and see what can be done.  Thanks muchly. 

Any pics of the boat !?!

Any pics of the boat !?!

[quote="535dboy"]
Any pics of the boat !?!
[/quote]

Now we see how you passed me on the post count LOL

[quote="Raj"]
[quote="535dboy"]
Any pics of the boat !?!
[/quote]

Now we see how you passed me on the post count LOL
[/quote]

It was an important request!

[quote="535dboy"]
It was an important request!
[/quote]

)

Sounds like a heat issue and the car trying to protect itself.  Not heard about not allowing manual change but anything is possible as all changes are controlled by the EGS module.

If you are keen on towing then it would be prudent to get a secondary cooler fitted for the gearbox fluid.
I was recommended to fit one, which i did, as i tow a rather large caravan...
Now the gearbox is sorted there has been no issues with heat.

Sounds like the box overheating and going into cooling cycle. This locks offf the top gears to keep the pump spinning nice and fast to pump more oil through the cooler.