318is Diff Questions

[Pal318is]

Guys,

My Diff has finally given up on me and has started to whine
I have a replacement, but i've had it stood still in my back garden for the best part of over a year I checked the oil in it this morning and it's nice and clear. I have some questions that hopefully you guys can answer.....

1. If the the oil is nice an clean as it is, does that mean that it's ok??
2. The Diff was rusted from the outside, which I have cleaned up, will that affect it if it is good?
3. How is the Diff oil changed, I haven't got a clue how to do it??
4. Is it easy to replace the Diff, I have tools and a little bit of know how, but maybe not enough??
5. Finally what numbers am I lookin for, to check the ratio on the Diff?

Any help would be greatly appreciated guys.....

Pal

[Lordschleife]

Diff for an iS should be the small case one (6 bolt i think?)
Ratio should be 4.10, this shoulod be on the metal tag on the diff - probably be rusty so you'll need to clean it to read it. If it has an S before the 4.10 then you're lucky and its a limited slip

I think they're fairly easy to replace, use a trolley jack to take the weight of the diff?

[Dan318-is]

a 3.91 will also work fine on an Is,

i would change the oil for good practice!

[Lordschleife]

But a 3.91 will be a medium case diff usually? Making it a bit more fiddly to fit

[Dan318-is]

But a 3.91 will be a medium case diff usually? Making it a bit more fiddly to fit

Medium case with 8 bolts yes, propshaft easily shortened im told; also diff can take a lot more abue than the small case ones

[Pal318is]

Nice one guys, but how do you change the oil??

Pal

[Jamesb318is]

There are two bolts on the rear of the diff cover. You will need a large allen key type bit to undo them. If rusty, may be worth cleaning out the bolt heads with a bit of WD40 etc so you dont round them out.
Make sure the diff is the right way up, and level. Undo the top bolt first (that way you wont drain all the oil and find the top one wont undo) then drain the oil from the bottom bolt.
Replace the bottom bolt - and washer (pence from dealer), and refill at top bolt until it pours out of bolt hole. Wait until the oil stops coming out of the top hole (make sure diff is still level) then replace top bolt+washer.
I normally use Castrol SAF-XJ.

[Dan318-is]

Were do you buy your oil james?

i cant find it anywhere except bmw; 40 quid for doing it they want!

[Jamesb318is]

'Buy' oil?!!! i find it in the drums at work!

[Pal318is]

There are two bolts on the rear of the diff cover. You will need a large allen key type bit to undo them. If rusty, may be worth cleaning out the bolt heads with a bit of WD40 etc so you dont round them out.
Make sure the diff is the right way up, and level. Undo the top bolt first (that way you wont drain all the oil and find the top one wont undo) then drain the oil from the bottom bolt.
Replace the bottom bolt - and washer (pence from dealer), and refill at top bolt until it pours out of bolt hole. Wait until the oil stops coming out of the top hole (make sure diff is still level) then replace top bolt+washer.
I normally use Castrol SAF-XJ.

Nuff Respek James....

Thanx for the feedback Guys, as before always appreciated.

[Dan318-is]

'Buy' oil?!!! i find it in the drums at work!

How much for a litre

[kevin316i]

Castrol SAF-XJ is for limited slip diffs, its available form the main dealers only. Costs about 25 euro per litre. Small casing diff takes 1L.

[Jamesb318is]

I can check what a staff discounted price would be if you want? I cant really go filling up bottles with the stuff, doesnt really matter when its my car, but i dont wanna take the !