Originally Posted by Krystian
I will have to talk to the Infinity Service dept next time I take it in and see what oil is OEM in there and if they could put that one in.
I am surprised that more people don't complain of this issue. I looked up that transmission model code, at 65% of C-class Mercs have that transmission.
Factory oil is Shell DCT-M1. It is incredibly difficult to buy that EXACT fluid. I tried to quote the viscosity specs of that fluid, originally, but I couldn't even find a Shell technical data sheet. That's why I fell back to the Amsoil fluid. However, I am confident that the Shell fluid has similar viscosity characteristics -- since both claim to meet MB 236.21 specification (MB Specs are strict
I'd be curious to see if you could even buy that exact fluid at your local Infiniti Parts Department. I expect they'll try to sell you an "equivalent" from another brand, instead.
Unless you have reason to believe someone changed your fluid to an incompatible one, then you should still have the factory fill in your QX30. The maintenance schedule says the transmission fluid and filter
should be replaced every 60k miles or 5 years, whichever comes first. If you want to do it sooner, then that's your call. Shifting quality can degrade as the fluid wears out. But if shifting feels "good" when the transmission is warm then I'd suggest that new fluid is not likely to improve shifting.
I have serious concerns that many dealers will not
be following the manufacturer-prescribed process for transmission fluid changes on the QX30. The Infiniti Service Manual is quite clear that the DCT filter MUST
be replaced as part of the periodic maintenance. However, I have seen too many dealers cut corners, and I fear many will simply use a fluid-exchange machine and call that "good enough". I do not think those machines are a good idea -- especially not on a DCT. They've been known to cause problems with conventional transmissions, and I think they're an absolutely terrible idea on a DCT. Dealers who use the machine do so purely to save their own time, and end up ignoring the transmission filter. There WILL be clutch material caught by the filter, and it MUST be changed, otherwise flow will become restricted and if you let that go on too long you're asking for a failure. Replacement doesn't seem particularly difficult, but it is time consuming. The following parts must be removed to access the filter:
- Engine Air Duct and Air Cleaner Housing
- TCM Harness (Connector)
- Left Charge Air Tube
- Engine Under Cover
- Oil Pan
Before you have a dealer change your fluid, make sure to confirm their pricing, and whether they change the filter. I would ask them lots of questions, and don't let them wiggle out with a non-committal answer like "we change it if it needs it, or we change it if it has one". I would make sure they confirm the QX30 does
have a filter, that they're aware of and familiar with how involved it is to access, and that they will
change it. Expect to pay several hours labor for them to do it right. This is not a "cheap" service.
MB 236.21 DCT ATF lists for $31 per quart. Online it goes for around $23.
The QX30 requires 5.125 qt of ATF (2WD) or 5.5 qt of ATF (AWD).
For labor, I'd expect around 4 hours of billable labor, plus/minus an hour.
Ultimately, I wouldn't be surprised to see a $600+ estimate for a dealer to PROPERLY perform a transmission fluid service. It would be even more if you're in a high-COL area with a shop that charges a premium.