2013 GL450 with 140,000 miles
I just had the transmission flushed at a transmission shop. Owner said the fluid was as black as he's ever seen and there is probably a problem causing the fluid to overheat to the point of burning. Any ideas on what would cause it and is there a fix besides a rebuild? Carfax report looked like it had been maintained at a MB dealer so I assume it was changed at 70,000 miles. I don't have any codes on my reader.

Since this was dealer maintained, is there a way to get the maintenance records?

 

I called the Dealer with my VIN and he gave me copies of all of the maintenance done on my wifes '13 GL450 when we bought it used from a local seller, not the dealer. He was really cool about it, said if I needed anything to give him a jingle, I will one day!

As far as black fluid? I would flush it again at the next oil change, there is still going to be black fluid in the Converter that doesn't get drained or flushed out.

Chad

 

I thought a flush cleaned out the torque converter? I'm concerned with why it's black. I don't want the transmission to give out on the road.

 

A Trans Flush is subject to interpretation, but from my experience the only way a TRUE FLUSH can happen is to disconnect the trans cooler line near the radiator and hook a machine to it that runs clean fresh fluid thru the pan, the trans, the trans filter and the converter.

A flush is also considered dropping the pan, changing the filter and adding new fluid. Some, however, would also call this procedure a drain & fill and not a 'Flush'. Following the procedure I explained earlier only changes the pan fluid (filter & Fluid) but does not change the Converter.

To my knowledge there is not a way to change the converter fluid without taking it somewhere where ALL of the fluid can be removed and captured and new fluid added via a machine that almost nobody has in their home garage. But these units are available at places like Jiffy Lube or your nearest Oil change facility.

I personally have never went into a Mercedes dealer to witness the use of this machine. Most will drop the pan, replace the filter and refill to proper levels. If you feel "iffy" about continuing to run the car with the remains of dirty fluid then do I said earlier. At your next oil change drop the pan, change the filter and refill. That old black fluid is coming out and if you do that once or twice more then the fluid would be clear.

DISCLAIMER: if the fluid continues to be black then most likely the clutch plates are deteriorating. Black Trans fluid means the fluid is oxidizing. But I still think fresh fluid does a hell of job in helping to make it last a long time. These cars, as most cars & trucks, benefit greatly in keeping fresh fluids in the vehicle. Motor Oil, trans fluid, differential oil, transfer case oil, radiator fluid and brake fluid, all make a big difference in prolonging the life of any vehicle.

Chad

 

I’m pretty sure the service interval is more like 50k. And a fluid change on my car alleviated a harsh 1-2 2-1 shift, it’s hardly noticeable now. I believe the solenoid might need to be serviced with the magnet procedure to rid of all the metallic dirt, but I’m not dropping the valve body to create more issues. Also note MB fluid can be dark blue and that’s not far from the color black to a unsuspecting person in the matter.

Did things get better when you changed the fluid? We’re there any problems before?

 

It didn't change anything, seems to run and shift about the same as always. I didn't bring it in for a problem, just maintenance.

 

This was a complete flush at a transmission shop.

 

Service Interval for my 14 GL 350 was 70,000 mi.

 

Change the fluid and don't worry about it. Too many miles to worry about and too many miles to fix something that is not broke.

 

You might be right. I thought there was a disclosure for towing and excess work. But I stand corrected.

 

It is not black. More like dark blue color. All good. OEM oil.

 

When I was researching it said the equivalent oil was Shell ATF 134 FE which was described as Red. If the work was done at a MB dealer it would have been blue?

 

WIS does not specify flush, which means forced fluid using pressure. My view is that 90% of transmission shops don’t use a pressurized flush.

WIS calls for drain and refill. WIS calls for torque converter drain, if a drain screw is present, which isn’t 100% of the cases. No pumped or pressurized flushing. Dealers follow WIS, that’s all.

A drain and refill replaces most of the fluid, but not all of it. It’s fine. Avoid overthinking.

Transmission servicing and spark plug torque and indexing are two of the most over-thought service tasks on this site.

Transmission fluid change interval for 166 platform is 60k miles.

 

Newer transmissions goes on blue. If some one put red ask them to drain and put blue.