MRLE550

Hello, first post.

I was driving my 2011 E550 4m on the highway at roughly 80mph, as I started going uphill the transmission starting slipping and revs climbing and I could not maintain speed. I got off the next exit about a mile down the road, I came to a complete stop and when i tried to pull away from the light the car would barely move. I was able to pull into a parking lot, i went to position the car after pulling in and didn't have reverse. I shut the car down waiting for the tow truck, when he arrived I started it back up and did have reverse. (i have a suspicion the car would have driven)

I had it taken to a local shop (only one who could take a look midday Friday). He is reporting no leaks of any kind (although it looked like it was leaking underneath where the car was parked, hard to tell with rain) and has taken the car on 2 drives of 15+ miles and has not been able to repeat the issue. He let the car idle for 25 minutes between rides, there are no codes coming up when checked.

Car has 130,000 miles, fluid was changed about 25,000 miles ago. The car is driven 50-75 miles daily with no previous issues.

Any thoughts would be appreciated, thank you.

matt

MRLE550

Another question about my question.

Could a bad battery cause this issue? Was just thinking that I haven't changed it since i bought the car 8+ years ago, the aux has been replaced but not the primary.

matt

Arrie

Could it be you lost hydraulic pressure in the gear box? Could this happen if fluid level is low and pump pick-up goes dry going uphill?

This means you would have a slow leak that took level down during the 25 000 miles you drove it since the fluid change.

I don't think the fluid can drain too low thru the transmission pan gasket so the leak would need to be somewhere else, like at the transmission cooler leaking out or into the engine cooling system.

Just guessing here...

MRLE550

Thanks Arrie, the shop said the entire underneath of the car is "dry as a bone", they cannot find any leaks anywhere. My first thought was low fluid as well, not really a way to check without servicing the transmission i guess.

matt

Just reread your comment, " into the cooling system" . Had that drained at the same time I had the transmission serviced last and it was "clean" for coolant anyways.

Arrie

But if it started leaking in the cooling system AFTER transmission was serviced, i.e., how is your cooling system NOW when you are having the problem?

ChrisHimself

Transmission service again bigdawg. The one 25k ago washed some grit around back into the new filter, clogged it potentially, and you're losing line pressure again. Loss of pressure causes slippage/chatter. I see this ESPECIALLY when it starts getting hot and you're in stop/go traffic. The newest ATF134FE stuff ages like milk. Its not a mercedes thing, Mercon LV doesn't really age well either.

Are you the first owner? How well has that thing been serviced? The NIGHTMARE scenario is that you have intermix between your radiator/transmission cooler at the radiator with coolant, can you check your coolant to make sure its not oily? Coolant has something in it that strips the glue from the friction discs which can total out your transmission. I've yet to see this happen but its possible with any car with this radiator.

I sell transmission services damn near almost annually and nothing fixes a car like maintenance. Having a W212 E550 myself I have a soft spot for you and I want to make sure I help you as much as I can getting through this.

Vaico has the best filter kit I use.
Filter Kit

If you wanna upgrade to 100% synthetic fluid, use preferred customer program to save 25%. This stuff ages and handles heat cycles much better, with better cold flow characteristics on those early morning drives.
https://www.amsoil.com/p/amsoil-sign...tf/?zo=7236674

If you have the patience to DIY this I can walk you through it over the phone, call me.

MRLE550

Thank you Arrie and Chris.

I am the second owner, I've had the car about 8 years for 100 of the 130k miles. I do most of the maintenance myself aside from the transmission service or when I just flat out don't have time. I live in PA so corrosion is an enemy here garage kept or not. I won't get into the whole story but a lightbulb went off yesterday when reading a post, makes me think i could have had an external leak near the transmission cooler(perhaps a seal/gasket/line). I've never really looked under the very front under panel, I'm going to pull that and take a look today along with seeing if anything is in the coolant.

matt

S-Prihadi

In a 2011 model E550 , the engine radiator is still sharing tranny oil cooler too ?

MRLE550

Ok, so I had some time to root around everything myself. There is absolutely nothing under the car fluid wise, anywhere. As far as transmission fluid in the coolant I'm not sure how I would tell. I mean I took a white paper towel and stuck it in the reservoir it came out like a clear blue. Nothing appeared contaminated, if it is like a head gasket event that's definitely not the case.

Otherwise, I'm going to throw a new battery in for my own sanity since it at least 8 years old. Next I'll schedule a transmission service and go from there. I just wish there was an easy way to check the fluid level.(Also for my sanity)

JettaRed

iTrader: (1)

Have you scanned the tranny for codes? My 2004 SL500 had the 1st gen 7G tranny. The conductor plate had a speed sensor that started to fail and had similar symptoms.

Before rolling out the parts canon, get the TCM scanned! Be sure to use a Mercedes-specific scanner!

Arrie

You can remove the transmission drain plug and add fluid. If you do this cold, there should be room for more fluid. If you add fluid to make it overflow and then let it heat up to the correct temp (80C?) it should overflow the same amount you added when it was cold. You would just carefully measure how much goes in and how much comes out. The difference would be how much it was underfilled or leaked out somewhere.

It is a job to do but at least it would tell if the fluid is at correct level. Maybe your indy did not fill it correctly when last serviced?

It just kind of points to the low level when slipping happens going up a hill but then it is fine later on flat. Perhaps you could drive the front wheels on a ramp and see if it repeats it?

ChrisHimself

My car did this 20k miles after a change. It wouldn't actually slip, but the shudder would rattle the entire cabin going up a hill or doing the 2nd gear start in hot weather after it'd be idling or sitting at a light for a bit. When you do a big transmission service after a long interval, you're washing a lot of grit into the new filter too. I'd just nail another one. I have a recipe for a super easy transmission service with zero expensive tools and it's foolproof as long as you're on relatively level ground.

Thats my anecdoctal evidence, obviously it could be something else but I reckon the fluid is real real dark I have pics of 20-30k fluid within the 60k interval that is cooked and smells absolutely vile.

JettaRed

iTrader: (1)

You should never do a transmission flush, forcing some cleaning fluid through the tranny and torque converter. That's where you can mess up a tranny. But regular fluid drain and fill (mileage or time) is mandatory.

ChrisHimself

the technique is called rinsing, you just push a little bit extra at a time, I just say flush so people get the idea. VAICO recommends doing this

JettaRed

iTrader: (1)

Is that using air, such as with this device, to get all the fluid out?

S-Prihadi

Yes it uses shop air to push out oil from TORQUE CONVERTER , when and if your TC does not have the drain plug.
It push from tranny filter port.