300TDi Auto not changing down

Hi All,
New to the forum and landrovers so please be gentle with me.

I've had a '97 300Tdi Auto with 35K on the clock for a few weeks now and it seems to have started sticking in 3rd or 4th gear when I slow down.

I presume it's sticking in a high gear as I have no power when I try to pull away and it throws out black smoke whereas I'm normally smoke-free.

The gearbox oil level is OK and is a nice red colour but could the condition of the oil cause this type of problem? The transfer box has a slight leak so the level may be a bit low and I'll be checking this tomorrow.

My other thoughts are faulty engine speed sensors or throttle position sensor although if I select N the engine revs up ok.

The problem has only happened on a couple of occations and selecting park, turning off the ignition and starting again resolves the problem. I do feel a clunk from the brake pedal when I restart which I presume is the gearbox returning to it's correct position.

Grateful for any suggestions.

Welcome Richardh to the forum,

I don't think u have a problem with the auto gearbox , u may feel the change up from first to second thats usual, and when accelarating forth down to third just before kickdown 'kicks' in but thats all. It shouldn't give any smoke from an engine that's only done 35k.

I'm not into diesels but with petrol there's fuel additives to add that would or should clear out the combustion chamber and valves of any muck, but also u may have a engine problem, i'm sure a diesel owner will be able to help u with that.

Revs do increase in N and P and the clunk or knock u may hear when starting is from the brake servo.

I dont think you have a g/box prob sounds more like EDC prob esp as switching you ign off then on sorts it. Being in 3rd for pulling away would not give you black smoke.
I think you need to take it and get plugged in for code reading.
HTSH

Have you dumped the EGR??? Sounds like my firs Disco (a 200 and it smoked like a train untill the EGR was given the bif)