75 KV6 Auto - Downhill Issue
 

Hello All,

Hope everyone is coping okay with these weird times.

Bit of a weird one, and was wondering if anyone had experienced similar.

My 2003 Tourer 2.5 Auto (62K miles) does a strange thing when its cold. Once its warmed up, the issue stops.

I live at the top of a reasonably steep hill, when I first start the car and head downhill, at around 30mph, the gearbox will change down, to aid engine braking - which I would expect. However, there is a faint feeling of surging as the rpm's waft between circa 1400-2000 up and down up and down. If I apply the throttle, it stops, and if I brake to a stop it stops.

It only seems to be happening when its cold, and the rest of the driving experience is fine.

My initial thoughts are that I should book it in for a gearbox oil drain and refill, but just wondered if I'm missing anything.

Stay Safe,

Martyn

Sounds like a throttle body rebuild is in order, when it’s cold and you rev up, do the revs ‘hang around’ a little before dropping back down to tickover?

I too live at the top of a steep hill, my v6 auto always does the same when it's cold. Don't believe you have a problem.

If you haven't evidence that it's ever been done, I'd change the gearbox fluid - you'd be amazed how much better it'll feel overall.

Carlube ATF-U is cheap enough and a good replacement fluid for our cars.

Autobox fluid changed, then back in 1 week later after running a few hundred miles to do it again, does make a remarkable difference, but not going downhill from cold. Once engine is up to temperature I do not get the same response.

Thanks for the info all.

I haven't got any evidence of it being done, so will get it booked in for that. The RPM's don't seem to hang around after a throttle blip, the engine runs very well. I'll start with a fluid change and see if there is any difference / requirement for further investigation.

Stay Safe everyone.

I've been having the same issue and am certain it hasn't got to with gearbox as I replaced the 2,4 brake duty (due to failure) solenoid and changed fluid but nothing changed with this issue the were no codes on the car as well but what I did find out was that it happened only when I filling up at particular petrol station so in my last fill up I avoided that petrol station and threw in an injectior cleaner just for good measure and the issue hasn't come back

Never had that problem but we live in Norfolk and there are no hills!:getmecoat: