LiquiMoly diff fluid

[dparm]

99% of users will never notice a difference, and they'll never pay for it to be analyzed to see if it was even working well for their application. You'll probably never hear any "good stories" or "bad stories". Learn to decipher the chemistry of the fluid, understand the spec sheet, and then analyze it in service to understand which fluid is the best fit for you.

SAF-XJ is an excellent fluid and that's why BMW makes it FF, but you are certainly welcome to pick a different fluid.

[E90M3velocity]

Well lm is already in the diff and i was just wondering if its working ok or i should be worried from being so loud.

[thekurgan]

Originally Posted by E90M3velocity

Well lm is already in the diff and i was just wondering if its working ok or i should be worried from being so loud.

I'm used to the groaning, and don't use the FM boosted stuff, but, if once you make the turn, and the groaning doesn't stop while straightening the car, there could be an issue. I really only experience this in cold weather. The noise is necessary for it to do its job.

[Vic311]

Originally Posted by kawasaki00

If it chatters too much it will create hot spots on the friction plates leading to a shortened diff life

This says it best ^

The occasional pop or grind is okay, but you should never be under the impression that routine sound from the diff is normal. I only use the OEM fluid with FM. It allows the diff to work quietly, which in the long run will minimize premature wear.

[elim11]

I used redline diff fluid. A lot of grinding noises. Tried making tight circles to lubricate..no luck.

Will have to switch to the unicorn BMW FM Fluid.

[jjw2331]

Originally Posted by kawasaki00

It is not the same though. The Mercedes Castrol is the same as the standard BMW. The one with Booster is another level above the Castrol. I bought the Mercedes (Castrol) and within 25 miles the diff was grinding. Drained it back out and got the boosted stuff for 40 per bottle and within 2 miles it was back to normal. I put the Castrol in our 328 and it was fine.
I also tried the Royal Purple with booster and it did not work either. The Valvoline didnt work either. We get allt hat stuff at work free so it was nothing more than my time to try it.

The more expensive Friction Modifier(FM) booster fluid provided by BMW, and used for noisy differentials, is Castrol SAF-XJ with FM booster. They just put the FM additive into the original fluid.

I don't know what you mean by another level above the Castrol? I believe the extra cost you are paying is for BMW repackaging and adding FM booster.

The FM fluid is really only necessary when there is chatter. It's not a superior fluid that has to be put in our diffs. If the diff doesn't chatter, there is no need for the more expensive fluid. Also, too much FM can alter the locking properties of the LSD and isn't good for differential seals. The more ideal method to reduce chatter would be to add small increments of FM until the chatter goes away. Unfortunately, we do not know how much FM BMW adds to the SAF-XJ fluid.

The best person to talk about these issues is Dan at diffsonline.com

[kawasaki00]

Originally Posted by jjw2331

The more expensive Friction Modifier(FM) booster fluid provided by BMW, and used for noisy differentials, is Castrol SAF-XJ with FM booster. They just put the FM additive into the original fluid.

I don't know what you mean by another level above the Castrol? I believe the extra cost you are paying is for BMW repackaging and adding FM booster.

The FM fluid is really only necessary when there is chatter. It's not a superior fluid that has to be put in our diffs. If the diff doesn't chatter, there is no need for the more expensive fluid. Also, too much FM can alter the locking properties of the LSD and isn't good for differential seals. The more ideal method to reduce chatter would be to add small increments of FM until the chatter goes away. Unfortunately, we do not know how much FM BMW adds to the SAF-XJ fluid.

The best person to talk about these issues is Dan at diffsonline.com

That's what I said. The standard bmw fluid is the same as the Castrol Syntrax. The FM boosted stuff has another bump in modifier.

[jjw2331]

Originally Posted by kawasaki00

That's what I said. The standard bmw fluid is the same as the Castrol Syntrax. The FM boosted stuff has another bump in modifier.

I see what you mean. Thanks for clarifying

[marksae]

Originally Posted by elim11

I used redline diff fluid. A lot of grinding noises. Tried making tight circles to lubricate..no luck.

Will have to switch to the unicorn BMW FM Fluid.

Did you use the fluid for LSD's?

[elim11]

Originally Posted by marksae

Did you use the fluid for LSD's?

I believe so..redline 75W-140.

[apecush]

Originally Posted by elim11

I believe so..redline 75W-140.

try some redline LSD additive...

[thekurgan]

Originally Posted by apecush

try some redline LSD additive...

Redline makes two 75-140, one with modifier, one without. If you go adding your own, add it in SMALL amounts at a time. 1oz or less would be enough of that 4oz bottle. Too much and it's open diff season.

[E90M3velocity]

Originally Posted by thekurgan

I'm used to the groaning, and don't use the FM boosted stuff, but, if once you make the turn, and the groaning doesn't stop while straightening the car, there could be an issue. I really only experience this in cold weather. The noise is necessary for it to do its job.

Cool, thanks!