Hi All,
Been a while since I posted, but I was wondering:
I am at 100K on my 2019 S560, and its been great, no real issues, very reliable.
I am going to bring her in for some work soon, and was wondering about the motor mounts.
I can get to the trans mount, no problem.
Is there any other way to do the front mounts without taking out the motor?
Thanks

Front mounts are a big job. Do you have any symptoms of worn mounts?

some ppl simply drop the cats and do lambda at that time.

I have the same car. I took it to the dealer for the gas line recall. They swore it needed mounts, but every indy shop I have taken it to said otherwise. Nor does it have any signs of needing it done.

OP lots more vibrations at idle but no misfires? If so it may be ready for mounts. I have not seen the mounts used in the 222 for bent-8 ... the design of the mounts for the bent-12 is very different from 220 and 221 chassis cars and are not deteriorating in my 222 S-65. With 145,000 miles on it. Hope they are similar for your bent-8 powered car. The 221 S-65 got mounts annually. Among other things.

I am not having any issues, I just like to refresh at 100k for good maintenance.
I have to replace the trans mount as I get a 'bump' when it hit the gas hard from a dead stop.....

I wouldn't replace the mounts until you have reason to...but replacing the trans mount will accelerate the degradation of the motor mounts

I heard someone mention this exact thing before but I can't understand why it is the case is it because the forces are unequal on one side (engine) to the other (transmission)?

It’s because the mounts all work in tandem. The transmission and engine move as one unit. When you replace one mount and the others are still soft it accelerates wear on the weaker mounts.

I see so sort of like mixing old and new batteries (in say a device that requires two batteries), which results in the new batteries being drained quicker?

I've seen the mounts on an S560 at 170k and they were still intact. I just picked up a customer who uses it as a rental car. It's also a 2019. I think you're good to go. It looks like the typical exhaust removal job with a LOOONG 17mm box wrench

Fair to say after all forum members that shared their experiences (thank you), OP should leave both mounts as is?

Not true. If a transmission mount is having an issue... replace it. Engine mounts are of a different design than the trans mount and live with different loads.

I'm not saying don't replace it, but replacing the trans mount and not also replacing the engine mounts will accelerate the wear on the older engine mounts.

Again... The loads seen in engine mounts do not change due to a fresh transmission mount.

Physics and my practical experience over 40 years of dealing with this junk agrees.

Seeing that the transmission and engine are hard connected with no give between the two, that doesn’t make any sense. Transmission moves, engine moves and vice versa.

Design of engine mounts very different from that of the transmission mount. Loads handled by engine mounts very different from the transmission mount.

In a 221 car the engine mounts failed early and often. I got to do two sets of engine mounts to one transmission mount in that car.

My 222 S-65 with 145,000 miles on it has not needed engine mounts yet. Transmission mount is doing fine as well. I have it on the hoist looking every time it gets fresh fluids. Mercedes changed design of engine mounts for the 222. They finally got it right.

The different design and loads don't change the fact that if the transmission moves the engine moves. Any load that impacts one mount impacts the other mounts.

I think the opposite would be true ie a worn trans mount would tend to accelerate the wear of the engine mount by resulting in more motion of the transmission which would exercise the engine mounts more. A new transmission mount would better carry any of the loads.

What would be more likely be the case, is that the worn engine mounts would tend to shorten the life of the new transmission mount.

Thats also true. The issue is having one mount out of spec and its impact on the remaining mounts. But, the engine mounts are also worn and have more slop by the time the trans mount is shot.

Thank you all for sharing your opinions, they are very useful and it is a great topic for sure.
So it is inconclusive? I mean the transmission mount is super easy to replace compared to the engine mounts so that might had been an incentive to replace it but looks like we can't come to a conclusion if it accelerates wear or decelerate wear of the engine mounts?

yeah the transmission mount is much easier and requires way less tools and it goes out sooner, it's preventing twist and maintaining the correct driveline angle. but really the carrier bearing would be the one that takes the bearing after the transmission mount goes out but usually I replace them as a trio anyway along with potentially the flex discs if the customer wants to pay

I see, will pay attention to the carrier bearing as well next time.

Easy test. If the engine is touching the plastic panels under it the mounts are sagging and ready for replacement.
In the E-55 it was if the engine is very close to the front sway bar they were junk.
222 uses a different design that are not failing annually.

Before all the heat shields hiding the driveshaft we used to be able to look for if it was straight. Sagging in front? Trans mount is junk. But current cars have so many heat shields hiding it.

When did MB switch to fluid filled mounts?