Allen key size - rear diff?

Sat Jan 14, 2006 9:26 am

Hi,

Can anyone tell me the allen key size that i need to change the oil in my differential on a 1988 325i? I know the gearbox is key size is 17mm. Is it the same?

Thanks for your help

Sat Jan 14, 2006 10:38 am

hi Wid, am trying to do mine at the mo, I've got 1 3/8 allen key which is slightly sloppy so must be 10mm, can't budge it with allen though so will have to go and buy one for a wrench.

Sat Jan 14, 2006 11:29 am

I've seen 2 different sizes for the diff plugs, 10 and 12mm

Cheers,

Iain T

Sun Jan 15, 2006 2:12 pm

Thanks for the replies. Went to Halfords and bought a 10mm allen key to fit socket spanner. I was unable to loosen the fill plug for the differential although I did manage to get the drain plug loose. i tried WD40 and about 5 mins from a blowlamp then an extension (i.e. big spanner) on the socket spanner but it wasn't going anywhere. Will have to ask my local garage to sort out as i have now rounded the plug too.

On another similar note, i did manage to change the gearbox oil (17mm allen key) after much swearing. Drained all the old dirty oil out and filled up with nice new 80W 90 transmission oil plus some STP gearbox treatment. There were many bits of swarf attached to the magnetic drain plug when i took it out. End result...... the gearbox now feels notchier than ever! I haven't run the car until it is properly warmed up yet though so hopefully that will make the difference. Can anyone explain this?