SAF XJ+FM diff fluid formula changed? Noisy?

[WOODOO]

I know there are threads on diff fluid here but I haven't read anything like this specifically so wanted to ask.

Background: I'm getting my diff resealed and bought all the parts + genuine SAF XJ+FM fluid but having a indy shop do the work.

Indy shop I'm taking it to said that they don't recommend the SAF XJ+FM because they said they've never used it without the diff being noisy at parking lot speeds. They said that the SAF XJ+FM formula changed some years ago. So they recommend either Red Line or LiquiMoly.

I've had no problem with Red Line (no FM added) as that's what's currently in my diff but I chose to splurge on the SAF XJ+FM this time.

So wondering if others have had issues with SAF XJ+FM before? If you were in my situation would you still have them fill it with SAF XJ+FM or use Red Line instead?

Worse case I can buy some Red Line and return the SAF XJ+FM to FCP. Thanks in advance for your guy's help.

[bavarian3]

I purchased 1yr ago and it cured my diff groans.

[Tbonem3]

Sounds like they're just making shit up.

I'm trying to imagine the scenario where the expensive, high quality, factory lube is not good enough, so let's use the cheap, medium quality luquimoly instead.

[maupineda]

I used Royal Purple in my diff build, new clutches. No groaning or grinding noises at all. I plan to change to the castrol OE fluid without the FM booster, the RP was just for breaking in the diff.

Most new fluids I have seen have the FM advertised on the bottle label, so most have some FM. I think the “special sauce” Castrol makes for BMW just has more hence the booster tag.

[Estoril]

SAF XJ+FM is the 'go to'.

[bavarian3]

I used Royal Purple in my diff build, new clutches. No groaning or grinding noises at all. I plan to change to the castrol OE fluid without the FM booster, the RP was just for breaking in the diff.

Most new fluids I have seen have the FM advertised on the bottle label, so most have some FM. I think the “special sauce” Castrol makes for BMW just has more hence the booster tag.

The castrol will cause groan fyi.

[chris719]

I used Motul Gear Competition 75W-140 and have had no issues so far. It's cheaper, includes FM, bright blue for easy identification of any leaks, and may have a superior base oil blend.

[samthejam]

I recently filled my diff with it, no issues.

[WOODOO]

I purchased 1yr ago and it cured my diff groans.

Thanks for the comment. I have no real groans now but I've never heard anything bad about SAF XJ+FM so glad to hear it worked as intended for you as well. Just gonna have them put it in. If it groans like they say I'll just swap it to Redline myself but I'm doubting it will.

[WOODOO]

Sounds like they're just making shit up.

I'm trying to imagine the scenario where the expensive, high quality, factory lube is not good enough, so let's use the cheap, medium quality luquimoly instead.

Yea when they told me that it seemed absurd. When I researched the fluid it seemed like people were always trying to find a shortcut but the SAF XJ+FM remained supreme. Is this what you run as well?

[WOODOO]

I used Royal Purple in my diff build, new clutches. No groaning or grinding noises at all. I plan to change to the castrol OE fluid without the FM booster, the RP was just for breaking in the diff.

Most new fluids I have seen have the FM advertised on the bottle label, so most have some FM. I think the “special sauce” Castrol makes for BMW just has more hence the booster tag.

I remember reading on one of online shops that does diff rebuilds recommended using RedLine or some other non-genuine fluid. I guess when you rebuild that changes what fluid works best so makes sense. Since I'm just doing a reseal and no mods, I would expect the SAF XJ+FM to work the best. We will see.

[WOODOO]

SAF XJ+FM is the 'go to'.

That's the conclusion I came to after researching myself as well. Was surprised to hear it not recommended by the shop but I'm going to have them put it in anyways. Will report back after the work is done and I run it for a little bit of time.

[WOODOO]

I used Motul Gear Competition 75W-140 and have had no issues so far. It's cheaper, includes FM, bright blue for easy identification of any leaks, and may have a superior base oil blend.

Seems to be the same price as Red Line. Any reason you ran this one over Red Line? Good to hear another option though that works. Thanks.

[WOODOO]

I recently filled my diff with it, no issues.

Thanks for confirming. Going to have them put this fluid in.

[chris719]

Seems to be the same price as Red Line. Any reason you ran this one over Red Line? Good to hear another option though that works. Thanks.

It's bright blue and I got it Amazon prime 😂