Boygenius33

Hey every one I recently purchased a 2008 C300 4matic sport in mars red from a family member who was the only owner of vehicle. I know the vehicle was serviced at the local Mercedes dealer it's whole life I have every service receipt and for some reason the transmission fluid was never changed. The vehicle is in fantastic condition and has 80k miles on it i would like the vehicle to last for some time longer obviously I'm nervous about the transmission , should I change it now at 80k or should I just leave it at this point since it hasn't been done ? I've heard and personally had experiences with other vehicles were changed trans fluid at higher mileage has caused failures .

shadenfroh

Dealers in my country don't keep record of transmission fluid changes (I've asked), since it isn't part of regular Service A/B schedule. I have the US service booklet and it doesn't mention transmission service anywhere, so my educated guess is the situation's the same.

It's always good to change the fluid. What you need to consider is how you change it. You can just drain it, or you can power flush it with a machine (the way some dealers do it).

I'd drain the fluid immediately, then change again in a few thousand miles and stick to the schedule after that.

I would not even entertain the thought of a power flush at 80 000 miles.

jlr82

I would have it changed even if it had been done once before, but I would have an authorized dealer do it (just what I would do personally). For the 2008's I believe the manual stated it only needed to be done once at 39,000 miles. Starting in 2009 the service manuals language changed and said it should be done roughly every 4 years or 40,000 miles.

Colin G

If unsure change it asap. You need to change the filter, gasket, pan bolts ect ect so have a dealer or reputable indy shop familiar with Mercedes do it.

Call around for prices.

shadenfroh

I think I should to elaborate on what I said earlier, because it's extremely important:

The danger of changing the fluid on neglected transmissions/gearboxes/differentials/engines/etc. lies in the fresh fluid and additives dislodging large pieces of gunk that start flowing around and do damage.

When you just drain the fluid, you're not applying pressure to the gunk that's collected inside. Particles do get dislodged by the fresh fluid, but generally at a slow enough rate as to not cause damage and most of them get caught in the filter anyway.

When you do a power flush, fluid is injected by a machine through the transmission at high pressure, hence the name "power flush". It washes away close to all gunk buildups and flushes them right out. If you do power flushes religiously at every service, there won't ever be enough junk to cause trouble.

If, as is your case, you don't know the maintenance history, it's very risky to perform a power flush. There could simply be too much filth inside. A regular drain, however, does not pose a danger and is all but mandatory.

Many mechanics will be reluctant to work on heavily neglected components, because there's always the possibility of something failing then and there which means they'll have to eat the bill. If you do decide to go with the dealer, be very specific that they shall not attempt a power flush.

Carsy

All the junk as you call it will be deposited in the bottom of the pan & on the magnet.

The pan should be removed & cleaned & the filter changed.

All the fluid should be removed ie the torque convertor drained via a drain plug or flushed as old fluid will oxidise the new.

In my opinion it is an old wives tale to not change trans fluid on a neglected auto.To let the transmission oil deteriorate further & collect more contaminants is putting your head in the sand.

In any case 80,000 miles is not completely neglected .

You should receive advice from a few experts who do this maintenance every day & see what they recommend.

Good luck & let us know how you go.

dennish

My indy who specializes in mb says emphatically to NEVER flush a mb transmission.Just drain and clean. Add new parts and correct fluid.

Carsy

Have a read through this :-

https://mbworld.org/forums/c-class-w...-tomorrow.html

pfarah77

I would just get the tranny fluid changed and consult with the tech at that time to determine fluid condition. Also, request that the torque converter be drained as well. I wouldn't worry too much just get it done ASAP.

Boygenius33

ive decided to do a fluid change and filter change, have an appt for tuesday , also just finished installing new shocks , lowering springs and new wheels!

Carsy

Good thinking. Make sure the torque convertor is drained or flushed so the whole system is filled with clean oil for its new start with you.:0

I changed my ATM fluid today.

dave2001auto

Typical flushing machine ATF just connects with hoses to flush tranny. In internal inspection nor changing of the filter. Instead of 9.5 liters ATF, 17 L are used. 7 L of extra ATF to pay for and no new filter.
only good thing about a flush is no point in which it tranny is starved of ATF.