Hi all,
My disco is behaving a little odd and I'm trying to get to the bottom of it.

First off, for a while, I've been getting weird random kickdowns on the auto box. I'll be driving along on the flat with a constant pressure on the throttle. Suddenly, the box will kick down, rev to hell, then go back into the 'gear' it was in before.

Recently, it's also been running hot: after just a 5 min drive I'll stop the engine and the fan will be running. Something must be wrong here.

Finally, when it's cold and I reverse out my driveway, then go into drive, I'll get the gearbox going into limp mode.

I've read briefly about the viscous coupling - what should I be looking for, and how much is it going to set me back?!!

Thanks in advance!

Sounds to me like the fluid level is low in the box.

I would first check the gearbox oil might be an idea to change the oil and filter while you at it

You don't have a viscous coupling (except in the engine cooling fan.....)

iansoady said:

You don't have a viscous coupling (except in the engine cooling fan.....)

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He means the torque converter

MJI said:

He means the torque converter

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Yes I do! what would be the symptoms of it being faulty, and how bad is the fix?

Cheers

Gearbox oil first - doesn't sound like TC

Auto box oil and filter was changed relatively recently, though - less than 10-15K miles ago. I'll get it changed though.

What about the throttle position sensor/sensor that checks for kickdown?

Loco said:

Auto box oil and filter was changed relatively recently, though - less than 10-15K miles ago. I'll get it changed though.

What about the throttle position sensor/sensor that checks for kickdown?

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Hi Loco, before you spend any money at all, check the fluid level in the autobox. The vehicle needs to be parked on level ground. It's easy and straightforward to do. I strongly recommend that you do this yourself to ensure it is done properly. It is not at all unknown for the garage to use the wrong procedure when re-filling which would give at least some of the symptoms you speak of.

Here is the correct procedure, step by step:

1. Get underneath the car and locate the 'level/fill' plug on the front face of the autobox sump. It will either be a Torx or Allen plug of approx 25mm in diameter. Identify which it is and what bit is needed to undo it - Torx or Allen;

2. The next part of this procedure needs to be done with a cold engine;

3. Now slacken but do not remove this plug - this is in preparation for what we are going to do soon;

4. Start the engine, allow to settle for a minute to a good tickover, now select each gear lever position in turn, pausing 2-3secs to allow drive take-up; R pause, D pause, 3 pause, 2 pause, 1 pause then back to P.

NB. LEAVE THE ENGINE RUNNING

5. Now get back under the vehicle, with a drip tray in place to catch any oil remove the level/fill plug. If the level is correct you should have a VERY small amount of oil start to gently seep out.

If none comes out, it means the level is too low and you need to top-up until it starts to flow gently back out. Then replace the level/fill plug and snug up tight.

It would be advisable to have 2 or 3 one litre bottles of Dexron III auto trans fluid in stock before starting this procedure, just in case.

Once the autobox has been checked/topped-up as above, go for a test drive and evaluate, then report back here.

Cheers and good luck,

Dave

Hi - I am having a similar problem, I have tried to check the oil level, I have the front wheels up on ramps, and believe I have run through all the gears properly, but when I remove the fill plug, there is oil still coming out. I am convinced my issue is caused by low oil, and thought with the vehicle lifted at the front would allow me to even "over" fill it slightly (probably not a good idea in retrospect)... however, as I say it still spews oil when I take the plug out. Yes the engine is running, I have gone through each gear. It started doing this last week and since "checking" the oil and thus losing some it is worse, hence my prognosis.

Any ideas?