BMW M5 Forum and M6 Forums banner

1 - 13 of 13 Posts

·
Registered
Joined
·
1,548 Posts
Discussion Starter · #1 ·
Sooo...
Are we supposed to use Castrol Saf XJ or Castrol Saf xj +fm for the differential..
I haven't found a clear answer online.. I don't wan't to put the +fm if its only for increasing the slip for the e46 m3 differential when its grinding..
I've got 60,000 miles on my 02.. Any suggestions guys?

And while I've already made a new thread.. whats the recommended OEM tranny/clutch fluid I should use? A link would be great!
 

·
Registered
Joined
·
2,271 Posts

·
Registered
Joined
·
7,572 Posts
TIS specifically states a number of differential oils that are approved outright. The note for Castrol is SAF-XJ.

Part numbers are in the TIS version I'm looking at have been superseded to 83221470080 which is a 55L barrel of the stuff.

The net of all this differential banter that has evolved on the forum recently is that the differential in the E39 M5 is nothing special. It is a standard clutch-disc LSD differential. It is specified to use 75W140 synthetic gear oil. Generally all high quality synthetic 75W140 gear oils already contain an LSD clutch additive which reduces/prevents disc chatter at slow speeds when turning sharply (they do so by lowering the static friction coefficient between the discs).

So in summary, you can use many different high quality 75W140 synthetic diff lubes in the M5 differential. If one is an OEM freak on fluids, the BMW fluid is one choice. Something like Mobil 1 is another choice.
 
  • Like
Reactions: Mike S.

·
Registered
Joined
·
2,271 Posts
In the same vein as CSBM5's sentiment, the recent general feeling seems to be that no gearbox oil is better than others, the main gain is to change it, fresh fluid over old juice that has seen god knows how many revolutions of the cogs is going to show an improvement. My only reason for mentioning the Royal Purple is that that seems to be the brand most are going for at the moment, the majority on the forum for my old car went for Silkolene Silktran, as this was felt to quieten the box, but again it was likely due to changing old to new that made the difference anyway.

One of the differences I DID see however with the Silkolene was that it made the box stiff as when it was cold, but this eased within a few miles, and was then fine and smooth to change.
 

·
Registered
Joined
·
1,548 Posts
Discussion Starter · #5 ·
Ok so any 75w140 will be fine..
I like oem parts on such a high model car..
So I will be buying the saf xj +fm for the diff..
 

·
Registered
Joined
·
1,548 Posts
Discussion Starter · #6 ·
Ok so any 75w140 will be fine..
I like oem parts on such a high model car..
So I will be buying the saf xj +fm for the diff..
 

·
Registered
Joined
·
506 Posts
I changed my original diff (and transmission) fluid with Royal Purple about 10K miles ago with no complaints.
 

·
Registered
Joined
·
1,760 Posts
I bought Royal Purple Max-Gear 75W140 for my diff yesterday, $18.99 for a quart bottle. They sell it in place like Kragen, Pep Boys. I looked into the Castrol one but it seems a lot harder to get. Will be putting the Royal Purple Synchromax in my transmission too.
 

·
Registered
Joined
·
622 Posts
Sooo...
Are we supposed to use Castrol Saf XJ or Castrol Saf xj +fm for the differential..
I haven't found a clear answer online.. I don't wan't to put the +fm if its only for increasing the slip for the e46 m3 differential when its grinding..
I've got 60,000 miles on my 02.. Any suggestions guys?

And while I've already made a new thread.. whats the recommended OEM tranny/clutch fluid I should use? A link would be great!



LOVE THE TITLE!!!!hihahihahihahihahihahihahihahihahiha
 

·
Registered
Joined
·
1,760 Posts
When I say harder, I mean you can't just walk into your local auto parts store and buy it off the shelf. Plus the RP stuff costs less. The parts you need for general maintenance are not that expensive by themselves but they add up. If you can't talk you way out of that warranty maybe your diff fluid need to be replaced because of the leak under the back of your car ;)
 

·
Registered
Joined
·
1,548 Posts
Discussion Starter · #11 ·
Quick question.. I can't seem to find how much fluid goes into the transmission..
Does anyone know the capacity of the tranny?
I bought 2 quarts of synchromax and that's all they had..
 

·
Registered
Joined
·
1,760 Posts
Some people put 1.5L, some 1.7, some 1.8. 2 quarts =1.9L so you might have just enough. I will be doing mine tomorrow and can give you an exact answer then. I read somewhere that it's 2L to fill from bone dry and I plan to get as much of the old fluid out as possible.

I have 3 quarts so if you happen to be near the bay area soon you can have whatever I have left over.
 

·
Registered
Joined
·
1,760 Posts
I did mine today and I reckon it took a little under 2 quarts. But I would still recommend you grab a third bottle. If you spill any you won't be able to fill enough so that the fluid comes out the fill hole again. If that happens you will never be quite sure if you have the right level.

Make sure your pump fits the bottle and that it works _before_ you drain the old fluid. Mine did not work so I had to make a pump out of the RP bottle itself with some plastic tube and an o-ring. This meant I could only get about 80% out as I bottle-fed the fluid in, so I had to open all 3 and had some spillage. PITA.

Other stuff to watch out for:
* When you open the drain plug the old fluid comes out thick and fast so be ready with your drain pan.
* You may see some drips coming out the fill hole before it's full. If you're not sure keep pumping and if it's full, more will come out.
* Transmission fluid is messy. Make sure you have plenty of degreaser and paper towel.
* If you get MTF in your hair don't worry, it shampoos out a lot easier than ATF. Trust me on this.

I didn't do my diff yet as the Autozone 14mm hex socket is too long and I didn't have a torch or other tool to break it down. But I noticed you could probably that one without a pump, the fill hole is a lot more accessible.
 
1 - 13 of 13 Posts
Top