Z300S Auto transmission fluid change

[WorldClassAccident]

It is raining so I thought I would have a go at changing the transmission fluid.

Here goes:

Get the filter, gasket and bolts


Drive around to warm to fluids and then raise the car and make it secure



Find the filler bolt and make sure you can loosen it. You don't want to discover it won't come loose after you have drained the 'box. On mine the bolt was really tight but once it moved it would turn by finger


Now find the drain plug


Don't forget to read the label, BMW have invented lifetime oil! Strange it works so well with a GM 'box


Remove the plug and let the fluid drain, not as bad as the diff oil was


Notice that as it drains, the drip point moves


so get your catch tank in the right place otherwise you will get fluid all over the floor


I am leaving it to drain now so will see what happens

[WorldClassAccident]

Removing the transmission sump needs a 10mm socket, a small 10mm socket


Carefully remove all the bolts leaving just the corner ones so it doesn't drop


Now removed the corner bolts


Now hit the bugger with a hammer to try and release it and then smack a chisel into the joint to try and separate it and finally it comes loose


Now I can see the filter and all the gasket bits stuck around the edge


So now I can see what makes the BMW lifetime oil so special, it is a browney red colour.


and full of little metal bits that haven't been picked up by the domed magnet in the corner


Yeah, real mucky


Remember that domed magnet? Turns out it was flat


Looks a lot cleaner now


Filter out and not looking that cleaner either


Wiped the worse of the fluid off the bottom of the box and started to scrape the old gasket off. I can assure you that lying under a dripping gearbox scraping old gasket off is not as exciting as it sounds

[WorldClassAccident]

Forgot to mention, take ALL of your spanners under the car with you.

17mm & 19mm for the fill and empty plugs
10mm for the sump bolts
13mm for the filter bolts
Hammer
Chisel

There must be a bunch of Bavarians laughing at the funny English man crawling under the car and back out for another spanner

[Jaguartvr]

Top Tip

On Ebay you can get extra long flexible universal auto gearbox dip sticks.
Just check the fluid level before you start so you can re check it afterwards to make sure you have the right amount of fluid back in. About a fiver delivered.

[Scottie22]

No wonder the magnet didn't pick up the bits if it was flat!
it needs charging up WCA!

[Danny_HUFC]

"Removing the transmission sump needs a 10mm socket, a small 10mm socket"

Do you get a normal 10mm and a small 10mm? I thought 10mm was 10mm?

[Scottie22]

I s'pect you get a "medium" one too..........

[WorldClassAccident]

Well all refitted and finished.

Old filter and new one


Clean transmission sump, gasket and bolts all ready to go on


New filter fitted


Shiny new bolts tighten and ready to fill


Just under 5 litres of fluid went in. About three and a half with the engine off, started the engine and cycled through the gears, back into park and the last litre and a half went in.

Left over fluid



I used a 500cc version of this oil syringe from Machine Mart. DO NOT BUY IT. It is extremely stiff to use, leaks at the handle end, lets air into with the fluid at the other end, has a hose that keeps kinking. Not please and now stink of transmission fluid.

BAD TOOL : https://www.machinemart.co.uk/shop/p...C-oil%20syphon

[WorldClassAccident]

Maybe I should have said 'narrow' or 'slender' 10mm socket

or maybe you just enjoy taking the piss ;-)

[Scottie22]

He who lives by the sword perish by it also.......

[WorldClassAccident]

Touche