[Concorde]

Hi guys, I’m about to change my manual transmission oil and was wondering if anybody ever tried to mix different grade oil to get a specific viscosity. For example I’m thinking about mixing 50:50 Redline MTL with either D4 or D6. I live in a fairly cold climate but I’d like to try something thicker than OEM, but still friendly in colder temps. My wife drives this car as well and I’m not sure she’d appreciate the feel of the MTL when cold....

My questions are : is there any downsides to mixing D6 with MTL ? Anybody ever tried something like that ?

[e90Mark]

UUC has something like that.

http://www.uucmotorwerks.com/html_te...nny_rattle.htm

[Concorde]

Originally Posted by e90Mark

UUC has something like that.

http://www.uucmotorwerks.com/html_te...nny_rattle.htm

That's cool, at least I know it's possible to mix oils. Their "recipe" looks a little too thick for my liking though...

[Concorde]

Here's the answer I received from Redline :

Thank you for contacting Red Line Oil, the D6ATF would be the recommendation in your transmission where the MTF-LT-3 fluid is specified.
If you wanted a little higher viscosity the D4ATF would be about 15% higher at operating temperature and a lower viscosity at low temperature, or could be mixed with the MTL if you wanted to experiment.

I'm pleasantly surprised they responded to my email, thumbs up to Redline. So they don't explicitly recommend against mixing oils; I think I’ll give it a try. Hopefully I can report back when done and once I have a few miles with it.

[Concorde]

Update : Here's my experience. I have an E90 335i 6Mt with 45K Miles and 1-2 shift was a little notchy. I intended to swith to Redline D4 as is slightly thicker than OEM, but once I was in the shop I decided to go with MTL as the D4 had not arrived in time to the shop.

Conclusion : I'm glad I switched to MTL instead of D4 or D6. It feels only slightly thicker than OEM and is smoother for the 1-2 shift, but I can still feel a little notchiness. I'd say it improved the feel by 30%, so not a night and day thing.

Also important to note : I replaced OEM trans support to RE support at the same time. I now feel a little more NVH in the shifter, but only because I'm paying attention : I'm sure my wife wouldn't notice. I feel this has helped too as the shifting action feels more solid, especially when shifting quickly in the higher revs (I'm running Cobb stage 2+)

Overall I'm very happy with the change so far, but remember I have not yet ran this setup in canadian winter so I might change my tune in January !

[bmwsinceday1]

You dont need redline for your MT oil. Just look for your specification at your local auto store, thats all. dont get stuck on brands.

Also, not good idea, IMO, to mix oils for to achieve viscosity- its not an exact science. get the spec needed, and use only that. good luck.

[bmwsinceday1]

You dont need redline for your MT oil. Just look for your specification at your local auto store, thats all. dont get stuck on brands.

Also, not good idea, IMO, to mix oils for to achieve viscosity- its not an exact science. get the spec needed, and use only that. good luck.

[mbanks21]

I wouldn't mix. Just get a dedicated MT fluid. I got a deal on Redline MTL so I'll be doing that this weekend.