why not?

[thamesc180k]

Hi all, the trans filter etc arrived today , so getting closer to flushing the fluid.
As the car has been doing nothing for a week or two ( not started or driven) the transmission fluid has drained down to the point of showing extra or overfilled.
Why not drain it and now and get most of the fluid out (i am just going to replenish what comes out) rather than taking it for a run to warm it up before the drain and only getting so much out (drained)?
thoughts?
Thanks Karl

 

[markjay]

Good point. Especially given that the sump will be removed and cleaned.

My thoughts are (and I'm just guessing) that a drain after a good run will get more sludge and debris out, assuming that - when cold - some of it may 'come to rest' in various places in addition to the sump?

@BlackC55 might be able to provide a qualified answer.

 

[Trickythemerc]

Don't forget to clean the magnet in the sump pan

 

[thamesc180k]

Good point. Especially given that the sump will be removed and cleaned.

My thoughts are (and I'm just guessing) that a drain after a good run will get more sludge and debris out, assuming that - when cold - some of it may 'come to rest' in various places in addition to the sump?

@BlackC55 might be able to provide a qualified answer.

i did think that too but i cannot see why the sludge etc wouldnt have dropped to the pan after the last run it had anyway, if it was going to get trapped it would anyway?

 

[W1ghty]

i did think that too but i cannot see why the sludge etc wouldnt have dropped to the pan after the last run it had anyway, if it was going to get trapped it would anyway?

Yes you could drain it from the sump , you might get just over 4L out ,then refill with 4L, then go for a drive or just run the engine and then drain, remove the sump and change the filter as you would for the gearbox service .

 

[thamesc180k]

Yes you could drain it from the sump , you might get just over 4L out ,then refill with 4L, then go for a drive or just run the engine and then drain, remove the sump and change the filter as you would for the gearbox service .

thanks , i did think of replenishing the fluid drained, and then doing it again with the filter and clean after the run. but thought it might be better to remove the existing sludge from the pan first so it didnt circulate or get picked up? I would have to change the filter at the same time though.

 

[W1ghty]

thanks , i did think of replenishing the fluid drained, and then doing it again with the filter and clean after the run. but thought it might be better to remove the existing sludge from the pan first so it didnt circulate or get picked up? I would have to change the filter at the same time though.

Absolutely , anything you can extra do will improve things .
I change the sump ATF every year (£28) by pumping it out the dipstick tube and refilling the same way . I then change the filter every 30-35k miles

 

[gusferlizi]

There's no sludge on automatic transmissions if your radiator has not crossed coolant into it.

Almost all transmission servicing (draining, flushing, must not overfill, etc) advice...are myths.

The oil doesn't go bad if the car doesn't sit rotting damp for years, and the filter doesn't clog if the clutch packs are not falling apart from damage.

A healthy transmission goes 200k+ miles on the factory fluid without any problems.