wtf.... Diff OIL, can't find a FM Booster

[Tbonem3]

Something to note, BMW sells the same Castrol SAF-XJ diff oil without FM modifier for the F80 M3 - P/N 83222357992 (1L = $38)

The E46/E9XM stuff specifically states SAJ-FX + FM booster with P/N - 83222282583 (0.5L = $46)

The + FM booster is quite a bit more.

Castrol, as an OEM, sells the fluid. I saw it on Amazon in a liter for $20 recently.

[bigjae46]

If a gear oil is marketed for limited slip diffs then it has some FM in it. If its just straight GL5 gear oil then it probably won't.

[0-60motorsports]

Get the redline:

https://www.fcpeuro.com/products/5w140-gl-5-gear-oil-1-quart-57914

Add a little bit of FM if your worried or if the diff makes any noise:

https://www.fcpeuro.com/products/limited-slip-friction-modifier-4oz-80301

[elbert]

I sorta just trusted FCP since they had it and they typically weed out the stuff that isn't quality, but now it's actually not available anymore.

Castrol Syntrax is available again at FCP.
I was worried there for a bit because I've had good results with it. I didn't add any FM to it.

Although now that I think about it, the factory BMW stuff isn't that much more expensive...

[0-60motorsports]

Castrol Syntrax is available again at FCP.
I was worried there for a bit because I've had good results with it. I didn't add any FM to it.

Although now that I think about it, the factory BMW stuff isn't that much more expensive...

I checked when I posted my reply above and it was still not available.

[bimmerfan08]

Counterpoint: Given the importance of the differential and the infrequency of changing the fluid, it is worth skipping the hassle and getting the factory stuff that is already measured perfectly.

You will indeed need three bottles. It takes about 1.2 liters.

https://www.fcpeuro.com/products/bmw...SABEgJDUPD_BwE

Interesting line in the description.

Note: SAF-XJ + FM booster For M3/E46. Production period up to Sept. 2001

[bimmerfan08]

I checked when I posted my reply above and it was still not available.

I see both Castrol and BMW fluids in stock.

BMW: Link

Castrol: Link

[0-60motorsports]

I see both Castrol and BMW fluids in stock.

BMW: Link

Castrol: Link

Oh cool thanks. Seems to be back in stock. But redline is half the price lol


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[elbert]

I checked when I posted my reply above and it was still not available.

I see both Castrol and BMW fluids in stock.

For the past few days, FCP said the Castrol was discontinued. 0-60 was right, I saw it too. Hence my post earlier today.

[bimmerfan08]

FYI, BMW 75W140 SAF XJ+FM Motorsport Differential Fluid is on sale at FCP.

Link