link for non FM rear diff fluid part?

[TX]

I'm trying to locate a part # or link for the NON FM version of the rear diff fluid on a E92, but all I can find is the new +FM fluid.
Thanks guys.

[jjw2331]

Are you talking about Castrol Syntrax Limited Slip 75W-140 (formerly Castrol SAF-XJ)? If you are, then your BMW dealership should have it in 55 gallon drums and can give you some in a container you provide. If you want 500ml (you need 3) bottles of it, Mercedes Benz service centers should have it. I believe they use this fluid for their limited slip diffs in the C63. I got them at my local MB dealership for about $20 a bottle.

[TX]

yep, that's the stuff I believe. Looks hard to find. I'm having diff grinding that I believe is more serious than the average noise. I'm going to take it to the dealer. Thanks for the tip. Also, the MB dealer stuff doesn't have the FM booster added correct?

[jjw2331]

Originally Posted by TX

yep, that's the stuff I believe. Looks hard to find. I'm having diff grinding that I believe is more serious than the average noise. I'm going to take it to the dealer. Thanks for the tip. Also, the MB dealer stuff doesn't have the FM booster added correct?

This the fluid I'm talking about:
http://lubsboutic.com/CASTROL-SAF-XJ

There is a little friction modifier (FM) in the castrol syntrax limited slip. I heard that most limited slip diff fluid has some FM in them. However, the FM booster diff fluid BMW sells for the diff noise complaint is castrol SAF-XJ with additional FM booster. So there is significantly more FM in the BMW one.

So in short, no, the MB dealer stuff doesn't have FM booster and is what BMW used in our cars when they left the factory. The FM booster BMW diff fluid is put in place when there is diff noise (usually a grind when turning). From what I read recently, FM booster fluid is now put in the diff regardless of noise when the diff is serviced and the fluid is changed.

[jjw2331]

If the grinding noise isn't reduced with the FM booster diff fluid BMW provides, then I agree, you should get it checked out.

[Vic311]

Originally Posted by TX

I'm trying to locate a part # or link for the NON FM version of the rear diff fluid on a E92, but all I can find is the new +FM fluid.
Thanks guys.

What are you hoping to achieve going with the Non FM? My understanding is the FM allows for more quiet diff operation. If your problem is not cured with the FM fluid, it is not going to be cured with the non-FM, and could mean something else is going on.

The FM fluid is also what is called for and this is the one I would use.

[TX]

Originally Posted by Vic311

What are you hoping to achieve going with the Non FM? My understanding is the FM allows for more quiet diff operation. If your problem is not cured with the FM fluid, it is not going to be cured with the non-FM, and could mean something else is going on.

The FM fluid is also what is called for and this is the one I would use.

I didn't want to change the operation of the LSD using a lube with more slip than the stock stuff. I understand they made it slicker to quiet the grinding. I made it 37K miles without grinding, now it grinds so why switch lube to something else that will change the way it operates if it worked well this far? I was thinking of just replacing the fluid with the stock stuff.

Now If BMW is putting the new FM stuff in all the diff's then that's a different story.

[Vic311]

Originally Posted by TX

I didn't want to change the operation of the LSD using a lube with more slip than the stock stuff. I understand they made it slicker to quiet the grinding. I made it 37K miles without grinding, now it grinds so why switch lube to something else that will change the way it operates if it worked well this far? I was thinking of just replacing the fluid with the stock stuff.

Now If BMW is putting the new FM stuff in all the diff's then that's a different story.

I wasn't aware there was a choice. When I went to the dealer they only had the FM in stock and is what they used. My understanding was that this was the right fluid. So when you say replace with stock stuff I think that is the FM, not the non-FM (at least for the M3)

[TX]

Originally Posted by Vic311

I wasn't aware there was a choice. When I went to the dealer they only had the FM in stock and is what they used. My understanding was that this was the right fluid. So when you say replace with stock stuff I think that is the FM, not the non-FM (at least for the M3)

BMW switched to part # 83222282583 which is the FM modified version. I don't have a date of this ISB to fix the issue of complaints of grinding rear diffs. Original diff fluid on our cars was SAF-XJ as mentioned above and is the non FM version. I do not know when the switch was made or what ships in there stock now, but the old stuff was still listed on the BMW operating fluids PDF from July 2010 as the approved oil.

[jjw2331]

Originally Posted by Vic311

I wasn't aware there was a choice. When I went to the dealer they only had the FM in stock and is what they used. My understanding was that this was the right fluid. So when you say replace with stock stuff I think that is the FM, not the non-FM (at least for the M3)

You're right. As of now, the fluid BMW will change your diff fluid with the is one with FM booster.

The stuff TX is looking for is the original differential fluid M3's came off the line with. It used to be the fluid they put in our diffs after 1200 mile break in or anytime you wanted your diff fluid changed. However, that's not the case anymore. FM only now.

I use non-FM booster Castrol Syntrax Limited Slip 75W-140 in my diff for similar reasons TX mentioned. Also, I was told by someone who works on diffs that FM booster can eat the seals in the diff which may cause some leaking over time. However, I can not say for certain it will happen on our differentials with the FM booster. My differential never had any grinding noise and saw no reason to switch to the FM boosted fluid.

[SenorFunkyPants]

Originally Posted by jjw2331

You're right. As of now, the fluid BMW will change your diff fluid with the is one with FM booster.

Is there any sort of paper trail noting this change? I hadn't heard that before.

[jjw2331]

Originally Posted by SenorFunkyPants

Is there any sort of paper trail noting this change? I hadn't heard that before.

Ask your service advisor. He/she should be able to print this out.

[TX]

Just an update, Mercedes sells a bottle of SAF-XJ 75W-140 Mercedes part #001989520310. It is $15.60 online for a 500ml bottle. They use it in their C63 LSD. I can't confirm though if it's actually syntrax or another Castrol product. I'm trying to locate photos now to confirm., but I might have to just drive down and ask for a bottle to see. $15.60 a bottle isn't half bad if it's the right stuff.

[jjw2331]

Here is a link for anyone who wants to purchase online

http://www.ecstuning.com/Mercedes_Be...310/ES1613859/

[jjw2331]

Here are some photos of the MB Castrol Syntrax 75W-140 (successor of SAF-XJ).

[TX]

JJW, awesome! thanks for the photos. That's the stuff. $15 bucks a bottle is a hot price compared to the new BMW FM boosted fluid at $50+ for a 500ml bottle. Wish I had found this sooner as I ordered some online from a guy selling it out of a 55g drum at $36 a liter. Sure hope he's not filling the plastic bottle with cooking oil ;-)

[jjw2331]

No problem TX! Glad I could help

[TX]

This is what I ordered. Fingers crossed it's not fry oil.
Color right? Worst case I'll run down to the MB dealer and grab a few of the bottles now that I know I can get it there.

[jjw2331]

yup. that color looks the same as mine.

Although this pic might may make it hard to tell since its a smaller amount compared to the bottle in ur pic.

[TX]

looks good . Thanks for all your help.
Have a good one.

[SenorFunkyPants]

Originally Posted by jjw2331

Ask your service advisor. He/she should be able to print this out.

Thanks for that, much appreciated.
I'm thinking they didn't put that in my car last year when they did the diff oil service as it still makes the same groan in certain circumstances.

[Jaymax85]

Is the MB stuff with the friction modulator, or not as suggested earlier in this thread?/