Autobox - sanity check me.

[Yugguy]

Ok, I know that if you want to do a proper full drain and fill, you should drain when hot and replace with hot fluid to get the right amount in. And you have to faff about running it and cycling through the gears and all the rest

But assuming the level is correct, on the Full on the dipstick, if I drain say 3 litres of cold just from the converter sump, and then add 3 litres of new cold, then my level should still be correct, and I have at least renewed some of the fluid?

I have the idea that I might do this yearly during the service, so no, I wouldn't be changing all the fluid but it would be partly refreshed every 8k miles.

 

[HDi fun]

I can't see why that wouldn't work. Just make sure you are using miscible fluids. I have heard of some issues mixing minerals and synthetics.

 

[T9 man]

As Paul said, you really need to double check the transmission oil going in. My own car as well as a few other models I know of are uber fussy and don't take kindly to some fluid makes.