What should Mercedes Benz ATF look like?

[adamg]

One of our customers stopped by our shop today (we're a heavy equipment shop, not cars), and wanted to show me a sample he had taken from his '98 Benz - 270k KM.

Long story short, tranny was slipping, he took it to his MB dealer who performed a fluid/filter change. He returned with the same problem, they said he needs a new transmission. He took it somewhere else, where they looked at the fluid, and took a sample out for him (no UOAs done).

The fluid had the viscosity of 2% milk - VERY runny, and it was VERY dark, it looked almost like black coffee, but no burnt smell. I assume they didn't flush the fluid, but just dropped the pan and refilled with a new filter.

So what should that fluid look like? Red? Same viscosity as regular ATF? Since it was done at a MB dealer, I assume it is MB fluid.

 

[StevieC]

Maybe the Radiator's antifreeze is leaking into the Transmission cooler and contaminating the fluid? Shouldn't be black like coffee unless the transmission is seeing severe heat or abuse... Should be red and look like regular ATF fluid.

 

[HTSS_TR]

The color of the new MB ATF is dark red and it smells like raspberry.

 

[adamg]

I'm not sure, I didn't see the car, so I wasn't going to get into any sort of diagnosis. I'm not experienced with MB, so I'll leave that to an MB expert. He said he always had the car serviced there since new, and doesn't sound like he ever changed the fluid. I told him that if he's never changed the fluid, 270k is pretty good for a tranny. (Not bad for a trans with regular service!)

I would expect that colour with that mileage, but not if they just changed it. Again, I've never seen MB fluid, so I can't say.

 

[Donald]

Well if he wanted to he could have the sample analyzed now. It should not not or ever be contimanited by antifreeze. If he has never changed it in 270K its now in need.

 

[The Critic]

270,000 KM or 167,700 is a lot of miles for an automatic transmission. Most of them are designed to last about 150,000 miles.

If it was a 722.6 transmission, he's lucky that it even lasted that long.

 

[HTSS_TR]

That MB owner should take the car back to MB dealer to complain about the ATF fluid condition. He paid several hundreds buck for fluid change, he should expect new fluid in his transmission, not mostly old fluid with only few quarts of new fluid mixed in.

 

[Kestas]

Is this one of those transmissions that uses carbon-based clutch packs, and hence a partial explanation for the black color?

 

[adamg]

I actually spoke to him again briefly, and he said he's going to go to a MB dealer and just buy a quart, and see what it looks like. I got the deer-in-the-headlights stare when I suggested a UOA, so I just left it at that. Hopefully the tranny shop can help him out.

Oh and by the way, that fluid/filter change was $500, new tranny - $6k!

 

[StevieC]

M.B. = Many Bills!

 

[adamg]

So true!

 

[HTSS_TR]

The nominal charge of synthetic oil+filter for most MB is $250 at my local MB dealer. But this cost includes 1 day MB C-class rental.

The MB owner should compare new fluid with current fluid, then complain to the dealer general manager that his current fluid is supposed to be like new fluid.