Motul recommendations for 6MT & Differential ('18 F80)?

[TopJimmy]

Hi All,

I'd like to get some advice on the correct Motul brand gear oils for the 6MT manual transmission and the rear differential for hard STREET use.

I've picked Motul brand because their new "Specific 5w30" is LL-01FE certified engine oil is $30+7 shipping on Amazon. This price level allows me to do a dump and fill at 5K intervals, in between my scheduled dealer L/O/F service intervals of 10K. In reading other DIY posts on the diff service there seems to be a need for a friction modifier in the gear oil, but there's much less info on the manual trans service.

For gear oils Motul offers the following:
- GEAR 300 75w90 = 100% Synthetic Ester base, API GL-4/5, not for Limited Slip
- GEAR 300LS 75w90 = 100% Synthetic Ester base, API GL-5, says for Limited Slip
- GEAR Competition 75w140 = 100% Synthetic Ester base, API GL-5/LeMans24h , says for Limited Slip

Which would be correct for 6MT manual transmission? (thinking G300 75w90)
Which would be correct for M-series rear differential? (thinking G300LS 75w90, which has a Friction Modifier to prevent chatter, since the diff has both limited slip and full locker capabilities)

If you guys swear by a different brand for a good reason please let me know which and why. I'm always happy to get more info and make better decisions.

Also, does anyone know if the Rear Diff uses the exact same drain plugs as the 6MT gearbox? I'd like to install an magnetic drain plug in both, and ECS has a nice one at a good price.

-TopJimmy

[rborane]

oem BMW 75w140 without the friction modifier and change every 35k-40k. Oils with friction modifier are not necessary and from what I remember BMW used to use FM and stopped.

[TopJimmy]

Originally Posted by rborane

oem BMW 75w140 without the friction modifier and change every 35k-40k. Oils with friction modifier are not necessary and from what I remember BMW used to use FM and stopped.

Is this what you do for both Diff and 6MT?
From what I see ECS offers the service kit (BMW SAF-XJ+FM) with the Friction Modifier, and Turner Performance offers the service kit (BMW SAF-XJ) without the added FM.

[rborane]

Originally Posted by TopJimmy

Is this what you do for both Diff and 6MT?
From what I see ECS offers the service kit (BMW SAF-XJ+FM) with the Friction Modifier, and Turner Performance offers the service kit (BMW SAF-XJ) without the added FM.

I have DCT so not sure about the 6MT fluid, but the part number for the correct diff fluid is 83222357992. ECS has the correct fluid somewhere on their site, but not sure if it is part of a kit. I would purchase it off of Turner.

[TopJimmy]

Originally Posted by rborane

I have DCT so not sure about the 6MT fluid, but the part number for the correct diff fluid is 83222357992. ECS has the correct fluid somewhere on their site, but not sure if it is part of a kit. I would purchase it off of Turner.

Thanks rborane!

Others,
Still looking for an answer on the MOTUL.

[TopJimmy]

bump

[Remonster]

Originally Posted by TopJimmy

bump

Motul DCTF for the manual transmission (yes, DCT for the manual). The factory fluid in the 6MT is a dual clutch fluid which helps with shift smoothness especially when the gearbox isn't fully warm. You could also use Gear 300 75w-90, that works well but I liked Motul DCTF the best in my personal M3.

Gear Competition 75w-140 for the rear differential.

[TopJimmy]

Thanks!

[SCS55]

Originally Posted by TopJimmy

Thanks!

Currently in my rear differential.

[GoodtoGo]

Originally Posted by SCS55

Currently in my rear differential.

This 👍

[JeffB-M3]

Maybe an impossible question to answer since responses are likely based on "feel" but I'm coming up on 50k miles on my 2017 6MT and am planning to replace all the major fluids (oil, trans, diff, coolant, brake). For those changing over to Motul, or any other brand for that matter, is there any appreciable difference in your direct experience? I'm sure there is research out there which provides evidence of "better" products but I'm wondering if the driving experience changed....preferably for the better. Years ago I had put Amsoil synthetic gear oil in my Audi manual transmission and the difference was night and day. Shift effort reduced, shift smoothness increased, trans temp decreased, etc. It made the driving experience much more enjoyable.

[SCS55]

Originally Posted by JeffB-M3

Maybe an impossible question to answer since responses are likely based on "feel" but I'm coming up on 50k miles on my 2017 6MT and am planning to replace all the major fluids (oil, trans, diff, coolant, brake). For those changing over to Motul, or any other brand for that matter, is there any appreciable difference in your direct experience? I'm sure there is research out there which provides evidence of "better" products but I'm wondering if the driving experience changed....preferably for the better. Years ago I had put Amsoil synthetic gear oil in my Audi manual transmission and the difference was night and day. Shift effort reduced, shift smoothness increased, trans temp decreased, etc. It made the driving experience much more enjoyable.

I have over 61,000 miles on my 16' six speed manual averaging over 22,000 a year on it.
I'm a big Liqui Moly fan oil, gearbox, rear diff, and have used Genuine BMW fluids, LM and for fun, only varied the gearbox and rear diff with Motul.
To be honest I cannot tell a bit of difference. Maybe, maybe, felt a little looser gear box when I went from BMW dealer fluid to Liqui Moly and Motul, but not enough to quantify a "noticeable" difference.
I hope that helps.

[Trevorstein]

Originally Posted by SCS55

Currently in my rear differential.

Ok., Great!

How much do I need to get...

* Tramsmission - Lts.??
* Differential - Lts.??


Cheers!

[ONEof500]

Originally Posted by Trevorstein

Ok., Great!

How much do I need to get...

* Tramsmission - Lts.??
* Differential - Lts.??


Cheers!

For the diff 2. It's one liter but you need a little extra to top off.

[Nothing]

I’m looking to revive this thread just because I recently was told not to use Motul 75-140w in my rear diff as it lacks the friction modifier and it’s an issue for the diff on M cars. This was told to me from a number of mechanics at a well-known BMW modification and repair facility. So I’m here to ask if there is a friction modifier that we should be adding in? Or as recommended by the shop should I just BMW differential fluid?

[TopJimmy]

Revived for Nothing

It has the friction modifiers…says Motul!
Go show the mechanics.

https://azupim01.motul.com/media/mot...0_20210712.pdf

[ron_s55]

They're talking about previous M3's that used SAF-XJ+FM which is with extra friction modifiers. On f8x, use SAF-XJ or similar, without the extra friction modifiers.