How often to change transmission fluid?
 

Does it need to be replaced or flushed? It is my understanding there is a difference.

Car is a 2014 C300.

Thanks

I recommend every 30-40k from new, that will keep the fluid pretty clean and keep the transmission in good shape. Never do a trans flush, they are known to ruin longevity.

Agree. Do not flush.

For your vehicle, Mercedes recommends every 70k. But, I recommend all my customers to keep the trans service interval at 40k miles.

Just curious, if Mercedes changed the recommendations from 40K to 70K starting in 2013, why do you recommend keeping it at 40K? I am have to believe Mercedes changed something for them to change the recommendation that much.

Spoke to my mechanic, he said they were NOT doing a flush, they were doing a full transmission service and that anyone offering to flush it was likely a scam. So, good to know. Thanks!

I have something in the mid 30's at the moment. thanks

My dealer recommended the Transmission Service at 70K which I now have. They quoted $650 for this service last year. Is this on par with the going rate? Thanks!

For my 2012 C300 with the .15 fluid, I have a written quote for $400 CAD from an independent MB specialist mechanic who will do the full service including torque converter drain/fill as per the latest MB WIS.

I pay 350$ CAD at the dealership, every 60,000km. I was surprised the dealer was so cheap!

This is probably not the full service including draining the torque converter which requires more fluid. Double-check since some dealerships don't train the torque converter unless specifically requested by the customer.

It is the full service, I had an issue with it the first time they didn't not drain the TC had to call MB CANADA. The issue was quickly resolved lol I've been 3 times since and on every invoice they state TC drained. I was really surprised with the price myself and it's been the same price all 3 times.

Marko, which dealership do you go to? I need to do the same and that price seems quite reasonable.

How did you get the impression that a flush will ruin the longevity of the trany ?

Please explain to me your view of the difference between a flush and a oil change.

i must say that I am excited to hear your answer, since it defies every logic.

London Ontario, I've also called the Mississauga dealership where I bought the car they had a similar price. The issue was the wait time to get an appointment.

I understand a flush is where you use other fluids(Sometimes with big promises) than the specified oil to clean out the plot, then add the oil.

Changing the oil, or I ask them to replace the oil, no other fluid types are involved.

This is my understanding of flushing anything. So if I ask them to flush the gearbox, I would expect me to be ready(financially) to have it taken apart in near future as well, more costs....

That is quite a misunderstanding. Flushing involves no other fluids, then recommended ATF fluid for the transmission, at least that's the way it should be.

Flushing means getting ALL the oil changed, in the system.
They connect a portable oil changer in the oil cooler circuit, let the engine run. They drain the transmission sump, change the oil filter. They pump in new fresh oil. By changing the oil several times, that way, you get a fully flushed transmission, running only fresh oil, no mix of old and new oil.

This way, with a flush, they get ALL the oil changed, and not only the volume in the sump of the transmission + a minor part on the converter, even letting the engine run, and shift through the gears, as recommended in many other post.
Some even drain the transmission again after flushing, change the oil filter once again, and top up with fresh oil.

Look at this video.

This is an example how it's done.
No rinsing fluids, or detergents should ever be used. Only the recommended ATF oil. A full flush will require approx 4-5 gal of ATF if the oil is very dirty, or less, if oil has only slightly darkened.