Auto transmission dropping into a low gear

IronGiant

@car-man they could find nothing wrong with the box on normal driving, but when they dropped the pan to look for damage and obviously give it an oil change spotted that the earth return strap was severed.  I have noticed this in the past and forgotten all about it as it never occurred to me the gearbox may need it's own earth.  Any insight into why it was important?

gibbo52

The earth strap is/was usually for any electrics on the engine or g/box, as they are on rubber mounts, the main item would be the starter motor.

outoftheknow

Is kickdown electric on these? If so maybe that was changing it down a gear or two? (Assuming it has more than three forward gears of course! Maybe Kia save money by using a 1970s auto box )

IronGiant

It's a 5 speed box   (  reverse) and if you move the gear lever to the left it has a rudimentary "manual" function with up and down...

outoftheknow

So to my point then - some electric gear change signals? Maybe the broken earth strap was causing issues?

IronGiant

That's what I'm hoping

car-man

Sorry, I've not been around for a while, I've been fitting a new kitchen...nightmare, took forever!!

I wonder if the earth strap was for a cooling fan or it's for some electronics connected with the gearbox. I doubt if it was the main earth for the starter as you would get symptoms of sluggish battery on starting and all sorts of niggly electrical faults.

IronGiant

Thanks!!