DCT fluid service - Use fluid besides OEM?

Just changed mine out for Amsoil DCT at 43k miles. Actually feels smoother during regular shifts and just as punchy when redlining in S6

nholmes wrote

For a fluid service that occurs, what, 70,000 miles I just paid out the nose and went with the OEM stuff.

Same!

For a low mileage car, is there a recommended time period to change the DCT fluid, say every 10 years?

jc68 wrote

For a low mileage car, is there a recommended time period to change the DCT fluid, say every 10 years?

I'd guess 3-4 years? Lubricants have a shelf life.

BTW...when I drained the redline DCTF after 1200 miles, it came out pretty much the same color new.

jc68 wrote

For a low mileage car, is there a recommended time period to change the DCT fluid, say every 10 years?

No, not really. They don't break down over time, but they do get contaminated.

I think 5-6 years is probably the longest I would go for a DCT in a performance car.

Resurrecting an old thread here. Has anybody used the Liqui-Moly 8100 DCT fluid? The shop I use pushes Liqui-Moly for everything, and I'm trying to determine if I need to fight them on it.

Can't say I'm loving the OEM fluid at the moment. Getting occasional violent clunks like redpriest described, as well as longer-than-normal delays and roughness when shifting from R to D. 30k miles since my last change.

Just a hunch but maybe make sure it was filled properly. I've been running the Motul fluid with no issues which is the same fluid redpriest reported issues on. Several others reported no issues with Motul which leads me to believe it maybe fluid level related. No experience with Liquimoly dct fluid.

Additionally, have you had the GTS gearbox flash done? Thats clears up some of the jerkiness.

NoCarrier wrote

Resurrecting an old thread here. Has anybody used the Liqui-Moly 8100 DCT fluid? The shop I use pushes Liqui-Moly for everything, and I'm trying to determine if I need to fight them on it.

Can't say I'm loving the OEM fluid at the moment. Getting occasional violent clunks like redpriest described, as well as longer-than-normal delays and roughness when shifting from R to D. 30k miles since my last change.

NoCarrier wrote

Resurrecting an old thread here. Has anybody used the Liqui-Moly 8100 DCT fluid? The shop I use pushes Liqui-Moly for everything, and I'm trying to determine if I need to fight them on it.

Can't say I'm loving the OEM fluid at the moment. Getting occasional violent clunks like redpriest described, as well as longer-than-normal delays and roughness when shifting from R to D. 30k miles since my last change.

I doubt that switching to that fluid will make much of a difference. If there is a mechanical issue in the transmission, fluids won't magically fix it.

The LM fluid will work fine, but a 30k change interval seems really short. Pretty much everyone who has posted the UOAs for the M-DCT has shown that the fluid has plenty of life left even at 50k.

eternallx wrote

Just changed mine out for Amsoil DCT at 43k miles. Actually feels smoother during regular shifts and just as punchy when redlining in S6

This is what I want to do.

Anyone here ever used Ravenol DCT fluid? Their spec sheet mentions BMW-DCTF-1. A local parts dealer offered this stuff for $15/L when quoting me for a new pan and gasket. Sounds a lot better than $37/L for BMW fluid, but don't wanna save a few bucks and risk losing any lubricating qualities.

Tewie wrote

Anyone here ever used Ravenol DCT fluid? Their spec sheet mentions BMW-DCTF-1. A local parts dealer offered this stuff for $15/L when quoting me for a new pan and gasket. Sounds a lot better than $37/L for BMW fluid, but don't wanna save a few bucks and risk losing any lubricating qualities.

Not a lot of info available on it, but it's probably fine. There are plenty of choices in DCT fluids these days. $15/L is actually a decent price. Other aftermarket options are Red Line DCTF (not crazy about this since it's ~15% thicker than OEM), Motul Multi DCTF, Torco DCT, Liqui-Moly Dual Clutch Transmission Oil 8100, and Fuchs Titan DCTF.

I would give a nod towards the Motul fluid since it has viscosity nearly identical to the OEM fluid (within a few percent) but has a viscosity index 21 points higher. That points to it being a higher quality oil. Price is on-par with the other aftermarket fluids and it can be obtained from a lot of different suppliers.

If you want the OEM fluid without the OEM price, just get Pentosin FFL4 since that is what DCTF-1 is. This fluid is the factory fill in VWs and Audis now, too. OEM DCTF-1 has the following specs, so if you're shopping around for other fluids, get the datasheets and verify they're similar:

KV @ 40C = 34.7
KV @ 100C = 7
VI = 168 (this is rather low, many aftermarket choices are higher, which you want)
Brookfield @ -40C = 7400

dparm wrote

KV @ 40C = 34.7
KV @ 100C = 7
VI = 168 (this is rather low, many aftermarket choices are higher, which you want)
Brookfield @ -40C = 7400

So is there a benefit in using any specific aftermarket oils? If a heavier oil is better for our DCTs, it would also have less potential to leak from the gaskets, correct?

Tewie wrote

So is there a benefit in using any specific aftermarket oils? If a heavier oil is better for our DCTs, it would also have less potential to leak from the gaskets, correct?

I see no reason to deviate on viscosity. There is no proof that the typical DCT oil viscosity (which is really just a 75w85) is insufficient. The gearbox was designed to run with that specific viscosity oil so why take chances? A thicker oil *may* provide better protection at higher temperatures, but it will also retain the heat more and potentially cause more wear when it is not fully warmed up -- the same as engine oil. And yes, a thicker oil *may* leak slightly slower, but that is putting a band-aid on a larger problem.

As I said above, an oil with a higher viscosity index will generally be a better choice -- much like it is with engine oils. The VI is an approximation of how the oil resists viscosity changes with temperature. Higher VI oils are generally blended from higher quality basestocks.

Ultimately, I doubt that you or the car will know the difference between most of the commonly-available DCT oils. They are all extremely similar and the UOAs have shown that the M-DCT isn't destroying these fluids; even at 50k they have plenty of life left, which is way better than what a typical MTF will show at 50k. My message to you is that you should really just get whichever DCT fluid is cheapest and/or easiest to get, and if you have multiple oils that are cheap/easy, get one with a high VI. Hence...my recommendation of the Motul fluid.

dparm wrote

VI. Hence...my recommendation of the Motul fluid.

Thank you for the insight and recommendation.

Taking care of full DCT service as I’ve just turned 90k miles.

One shop uses Motul, one uses Redline, and the one I think I’m going to have do the work uses LiquiMoly… but I may just provide Pentosin…

Thanks for all the replies

I might be wrong or might be some Europe rebranding etc but i think
Fuchs Titan FFL-4 and Pentosin FFL-4 should be exactly the same.
Fuchs owns the Pentosin brand since 2015

I provided Pentosin and didn’t think I’d notice any real difference after the service, but the car feels extremely smooth