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Concerning changing the front Diff fluid, my indy (who is not a MB expert) says he could not change the fluid because it did not have a fill hole - only a drain hole and would require a special tool that they did not have. I checked ChatGPT and it said that a fuel pump of some sort would be needed, but no other "special" tool.
I am wondering what to do about this. Any suggestions?
Concerning changing the front Diff fluid, my indy (who is not a MB expert) says he could not change the fluid because it did not have a fill hole - only a drain hole and would require a special tool that they did not have. I checked ChatGPT and it said that a fuel pump of some sort would be needed, but no other "special" tool.
I am wondering what to do about this. Any suggestions?
Easy job, use the drain as a fill port with a few tools, transmission adaptor attachment, check valve, and fluid pump.
The transmission fluid fill adapter ATF109 also fits in the front diff drain hole. The transmission and front diff also use the same drain plug gasket.
I used an inexpensive fluid pump to pump in the differential fluid. At the time I used quick connect fittings but have since replaced them with an inexpensive shut-off valve.
I drained the old fluid and measured, it happen to be the same amount the manual says it holds. So I pumped in the same amount plus a little bit extra for any drips when installing the drain plug.
One additional question, and just to remind everyone, I am talking about my 2014 E350 4matic with 103K miles. I am thinking of getting the motor mounts and transmission mount done preventively next.
Any thoughts on this? ChatGPT seems to think it is pretty important to do.
I wouldnt consider engine and trans mounts part of preventative maintenance. I would replace them if they needed to be replaced.
When I got my current W204 I was feeling a slight vibration at stop lights and the idea of engine mounts got in my head. That was a few years ago, still havent replaced them and car runs/drives fine, great actually.
Mines a 2010 with over 160,000 miles on it and there is always something to do with the car as far as maintenance and fixing. I have a list of things I need to do, want to do, and should do. The only thing I have not done yet in the MB Maintenance manual is replace the fuel filter at 15yrs/150,000 miles. That is something i'll wait for issues to develop then replace if needed.
If you want to get the engine and trans mounts done its not like they need to be replaced at the same time either. The trans mount is fairly simple to replace. The engine mounts can be a project depending on engine and RWD vs 4matic. On my car the exhaust manifolds are so close to the mounts I can not even fit the wrench they sell for the bolts, id have to modify it or remove the exhaust manifolds.
Here is what ChatGPT says:For an 11-year-old Mercedes E350 with 103,000 miles, replacing worn engine and transmission mounts is important because those rubber components have quietly been doing a big job for over a decade — and by now, they’re almost certainly degraded. Here’s why that matters:
🔧 1. What the Mounts Actually Do
Engine and transmission mounts have two core purposes:
Support – They hold the heavy engine and transmission in correct alignment with the chassis and driveline.
Isolation – The mounts are made of rubber (and sometimes hydraulic fluid-filled) to absorb engine vibration and prevent it from being transmitted into the cabin.
When new, they let the drivetrain move slightly but stay aligned and smooth.
⚠️ 2. What Happens as They Age
Over time — especially by 100K+ miles — the rubber or fluid inside the mounts:
Dries out, cracks, or leaks (in hydraulic mounts)
Loses elasticity, so it no longer isolates vibration effectively
Collapses slightly, lowering the engine and changing driveline angles
This can lead to:
Noticeable vibration in the steering wheel, seats, or floor at idle or under load
Thudding or clunking sounds when accelerating, decelerating, or shifting (engine lifting or twisting excessively)
Premature wear on exhaust flex joints, driveshaft couplings, or transmission linkages (due to misalignment)
Stress on wiring, hoses, and A/C lines that move with the engine — they can stretch or rub through when the engine sits lower or rocks too much
🧩 3. Why Now — 11 Years / 103K Miles
Mercedes mounts typically last 80–100K miles, sometimes less on models like the E350 where the engine produces decent torque and heat.
At 11 years old:
The rubber has aged naturally — heat, oil exposure, and ozone all degrade it even if the car wasn’t driven hard.
Engine vibration at idle (especially with the A/C on) is often the first giveaway.
If you feel the car “kick” a bit when shifting from Reverse to Drive, or hear a dull thump, that’s also a sign.
Replacing them now restores the smoothness the car had when new and prevents secondary damage.
💰 4. What You Gain by Replacing Them
Quieter, smoother operation at idle and in gear
Sharper shifting and throttle response (transmission linkage geometry is restored)
Reduced cabin vibration and harshness
Protection for other drivetrain and exhaust components
Avoiding the “cascade effect” of worn mounts stressing nearby parts
🛠️ 5. Bottom Line
At this age and mileage, mount replacement isn’t just preventative — it’s restorative.
You’re getting ahead of potential driveline wear and regaining the refinement that Mercedes engineers designed into the car.
Many owners who replace them around your mileage say “it feels like a new car again.”
Engine and tranny mounts are comfort consumeables.
The higher the degree your are in-tolerant of vibrations because you know your car super smoothness when it was stiill in "virgin" state...... the faster you will replace all those 3 mounts.
You wont believe how often I replaced all 3 of these mounts.
At such mileage, replace them all already... no need to wait.
I bet the rubber flap is already kissing the engine mount main base and waiting only for louder knock.
Above is 71,000 KM and 11 years old, W204, C200. The more powerful the engine, the more agressive you drive = faster engine mount wear.
=============
This is not yet knocking but high vibration example of above's C200 W204 when at 83,000KM mounts replaced and my own low mileage 18,000KM engine mounts .
83K KM on my country road/use, the equivalent torture will be 100K miles in USA at the least.
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