Xantia auto gearbox conundrum

[davewithington]

Here's something interesting, if puzzling.

A while ago, I asked the forum about a problem I had with my 4HP18, which was shunting up and down between gears just on the change point, at times.

The consensus seemed to be dirty fluid (changed a few times) or governor seals.

Well......I had the head gasket changed a couple of months ago, it was leaking on the back right hand corner as they do, and when removed it was also blowing between cylinders two and three just a wee bit. Certainly noticed a difference in performance since it's been changed. But, and here's the conundrum, since the change my gearbox has been near perfectly well behaved, apart from being a bit clunky when cold in this winter weather. The shunting has gone completely.

Other auto gearboxes I've had experience of, like the GM four speed and BW boxes, have some degree of vacuum control. Does the 4HP?

Any other thoughts?

[CitroJim]

Hi Dave,

If it was an AL4 electronically controlled autobox then I'd say yes, quite possibly. I've known engine performance have a profound effect on the electronic 4HP20 as fitted to the V6 Xantia for instance but as I believe yours has the 4HP14 fully old-school mechanical-hydraulic 'box then not really but if the engine was really, really down on power then possibly...

Otherwise, just coincidence and the fluid changes finally doing some good!