When the E9x (2008-2013) M3 first entered production, the fluid spec for the manual transmission (Getrag GS6-53BZ) was MTF-LT-2. This was a 75W-80 fluid.
Then, just a few months into production, BMW changed the spec to MTF-LT-3. At the time, this was a 75W or 75W-80 fluid, slightly thinner than MTF-LT-2. Previous production dates were not back-specced for the new fluid despite having the exact same transmission (same part number).
Some time over the next few years, MTF-LT-3 became a 75W-90 GL-4 -- around twice as thick at 100º C. BMW continues to insist that this is the correct fluid for all cars produced after the switchover, but not for cars produced before the switchover.
Meanwhile, a few of the biggest and most reputable vendors continue to insist that MTF-LT-2 is the correct spec for ALL 2008-2013 M3s, citing BMW fluid guides that say as much.
MTF-LT-2 is no longer made, and the Pentosin-labeled version (MTF2) was discontinued recently. The replacement is Pentosin FFL4, which is apparently the same fluid but tweaked for DCT usage and GL-5 specs.
Anyone know what's behind all this? It's a bit ridiculous. Why did BMW change the spec a few months into the car's production run? Why were older cars with the same transmission not back-specced? How does it make sense to stick with the new spec even when its viscosity changes? Why is that not a new spec?
If anyone has some insight, it would be greatly appreciated!
Then, just a few months into production, BMW changed the spec to MTF-LT-3. At the time, this was a 75W or 75W-80 fluid, slightly thinner than MTF-LT-2. Previous production dates were not back-specced for the new fluid despite having the exact same transmission (same part number).
Some time over the next few years, MTF-LT-3 became a 75W-90 GL-4 -- around twice as thick at 100º C. BMW continues to insist that this is the correct fluid for all cars produced after the switchover, but not for cars produced before the switchover.
Meanwhile, a few of the biggest and most reputable vendors continue to insist that MTF-LT-2 is the correct spec for ALL 2008-2013 M3s, citing BMW fluid guides that say as much.
MTF-LT-2 is no longer made, and the Pentosin-labeled version (MTF2) was discontinued recently. The replacement is Pentosin FFL4, which is apparently the same fluid but tweaked for DCT usage and GL-5 specs.
Anyone know what's behind all this? It's a bit ridiculous. Why did BMW change the spec a few months into the car's production run? Why were older cars with the same transmission not back-specced? How does it make sense to stick with the new spec even when its viscosity changes? Why is that not a new spec?
If anyone has some insight, it would be greatly appreciated!