FrostedLogic

Just dropped the pan on my transmission because my transmission would slip after 30ish seconds being in gear into "neutral" while the display shows in gear, the fluid was brown and the bottom of the pan was grey, figured the clutch on my torque converter was probably gone but was also met with a bunch of small metal shavings, threw up a huge red flag for me, what should I do?

BOTUS

conventional auto gearboxes never slip in to neutral - they don't work like that

they work by the fluid applying pressure on and off to many wet multi-plate clutch packs - depending which is in use, it gives the various gear ratios
the electro-hydraulic solenoids that do the work to get the various clutch packs operating can fail or block.... the tiny amount of swarf in your box is "normal" on these hideous joke boxes Merc peddle. you need someone to tell you whats going on by looking at the fill rate adaptions of the solenoids... highly likely a full rebuild will be needed, if its not a failed or blocked solenoid

Senecat

Pull the TCU and pick up a used box.

vettebk

My S600 5 speed automatic transmission failed at 75K miles. Same story. Metal filings in pan. No pressure after warm-up. Replaced with a Mercedes remanufactured transmission on the extended warranty after their insurance adjuster visited the car and actually examined the codes. Approved the claim for transmission immediately. Also asked for a replacement torque converter and TCU; and extended warranty company denied the claim. I paid for it anyway since I love the car and wanted it properly repaired. Total bill was $9800 and I paid $4K; extended warranty paid $5800. You may be able to do it cheaper with a used box. Depends on how long you plan to keep the car.

W205C43PFL

What was the code stored?

nath_h

Yikes. I'm down to 3 months on my warranty. I'd have a hard decision if I got a $9800 bill next year.

FrostedLogic

Would a fluid change do the trick to get it running to a rebuild shop?

Senecat

It's toast bro. Drop it there in your garage, swap out the TCU and bolt up the used box. They don't weigh anything. I used to bench press Chevy TH350's into Camaros.

vettebk

I would never buy a used Mercedes especially a V12 without an extended warranty. I am just sorry I didn't buy more than 4 years and 50K more miles from purchase date. On the other hand, I love this car. It is a great platform. I don't mind the extra costs of maintenance. I can't really afford a new one, and if all goes well, I will buy a 2019 S class Coupe with a V12 (and an extended warranty!!) in the next year or so. Not sure I can afford that either, but it is on my bucket list and I am 73 years old.

BOTUS

specialist will rebuild - they do it all day long - I expect many could do in their sleep

the real cost aside from getting the box out - will be the need to buy a TC as the lock up clutch is also made of chocolate

s5benzo

I would change the filter and add some fluid to see how it behaves. Might be able to nurse it to repair shop if you are not doing it yourself.

BOTUS

if you have a S600 these eat gearboxes every-time anyone notices the car was fitted with a throttle pedal - 30k mile rebuild is common - they make the 7G look like a good choice

JohnLane

They live a LOT longer when fluid gets changed with regularity.

Five speed box in my 221 S-65 was a happy camper at 150,000 miles when I traded out of that car for my current steed.

I’m fond of doing a drain and fill every other engine oil change. Your 221 cars have a dipstick tube, drain plug in the box and in the torque converter. Easy peasy.

BOTUS

the way to make it last is to forget the last 2/3rd throttle travel - go there and fit a new gearbox when you get home from the short drive