[Hauteknits]

Hey guys, doing a trans swap in the next week or so and I need to buy manual transmission fluid for the trans. I'm 99% sure that the factory recommendation for my trans is LT3, which is GL-4 rated and 75w90. I've heard people recommend royal purple max as well as redline d4, but I'm honestly not sure what to go with. I live in AZ so cold temp performance isn't a huge issue. Also side point does any one know the oil capacity for the GS6-45BZ?

[whyzee125]

Everyone I've seen who runs a non-factory fluid raves about it at first impression but then ends up trying something else in a month when their gears start feeling crunchy. I'd find the OE BMW fluid if possible.

[335i54n]

about 2 qts, oe fluid is like 75/80 vis @ 7.5 ish which it seem is a little thin imo for hard/hot driving. i like redline mtl vis @ 10 or driven synchromesh vis @ 9 iirc

[Tambohamilton]

I replaced mine as a maintenance item a while back, and used some Fuchs 75w80 stuff (can't remember exactly what now). The oil that came out looked clean, and the new oil didn't work so well. Replaced it with Febi branded stuff matching the OE spec. That didn't help much. Now on Liqui Moly Top Tec 1100 ATF, which is better but not perfect. Might switch back to OE if I can be bothered or feel particularly flush sometime. Have heard good things about Redline MT-LV too.

[cookiemontis]

Are you sticking with the gs6-45bz or did you pick up a gs6-53bz? Fluid capacity should be close on either and 2 qts will cover it. Regarding fluids , I have tried the redline gl4 and honestly it just made shifting in cold weather worse. After I swapped to a gs6-53bz I used Chevron Synchromesh and it was a lot cheaper and I have no complaints.

Can I ask why you are replacing your transmission?

[Xalithar]

For that transmission i would buy 2qts for it. if you want to go with the original fluid the bmw part number is 83 22 2 167 666 (MTF-LT5). This was quoted off the Bentley manual, but for some reason it did not say what the capacity is for fluid swap. All the other transmissions did not go past 1.6 qts. I went with the redline and saw the synchos engage a tad better. The Bentley manual also recommends replacing the drain and fill caps but the torque is only 26 ft/lbs. i did but you don't have to.

[Hauteknits]

Kinda dead thread but 3rd gear was no more. I've decided on Royal Purple Synchromax. Initial impressions are great. 2 qts was the perfect amount, had a little bit extra. Hopefully I don't end up swapping back to factory oil but we'll see