W212 Front Differential
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Junior Member
Joined: May 2009
Posts: 64
Likes: 3
From: Texas
2013 E350 Wagon
W212 Front Differential
At 135k the front differential began to hum and coming home on the freeway gave loose inside and had to be towed the rest of the way. Unsure what was going on I replaced the right front axle from where the rotating clunking was coming from to no avail.
It seems apparent that I will now ave to replace the differential and am shopping for a low mileage used unit.
My question is: in order to pull the differential it seems that you have to "remove" the sub-frame. Not having done this before I would like to know if that means I will have to support the engine from above while ding this, or not? I can see that removal of both front axles will
be required and I will replace the driver's side axle bearing along with seals.
But y main concern is what has to be supported in order to get the dang sub-frame out?
Appreciate any help in advance!
It seems apparent that I will now ave to replace the differential and am shopping for a low mileage used unit.
My question is: in order to pull the differential it seems that you have to "remove" the sub-frame. Not having done this before I would like to know if that means I will have to support the engine from above while ding this, or not? I can see that removal of both front axles will
be required and I will replace the driver's side axle bearing along with seals.
But y main concern is what has to be supported in order to get the dang sub-frame out?
Appreciate any help in advance!
MBWorld Fanatic!
Joined: Oct 2002
Posts: 4,999
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From: Cincinnati
2010 E350 4Matic
I had my front differential replaced and they dropped the front sub-frame to do it. I was going to put motor mounts in anyway and at least got that part for free. I think that you will have to support the engine.
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Joined: May 2018
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From: Sammamish, WA
2011 E350 Wagon, 2010 GL450
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From: San Jose, CA
11 E550, 16 AMG GTS, 13 S550
Youre going to support the engine from up top , disconnect the axles so you have clearance, engine mounts come off, and work the rest off.
Leave the knuckle and arms attached if you can work around them, otherwise I rarely trust ball joints and bushings to come back together without needing an alignment/replacement. This is a great opportunity to do a lot of repairs while youre down there, tranmission mount is only 30 minutes way once youre down there.
Have you EVER replaced the gear oil in the diff? It's important on the front differential cars to replace the fluid specifically in that, I don't know why it heats up more than the rear one, but I pull 120k 75w90 pretty routinely from the rear and it looks new ish, but the front diffs are always trashed oil that smells particularly awful, I think the amount of sulfur in the anti wear additives cooks off and makes it smell that way but yeah it's usually cooked. The newer 4matic E63S thankfull have a published interval so those owners should be ok.
Leave the knuckle and arms attached if you can work around them, otherwise I rarely trust ball joints and bushings to come back together without needing an alignment/replacement. This is a great opportunity to do a lot of repairs while youre down there, tranmission mount is only 30 minutes way once youre down there.
Have you EVER replaced the gear oil in the diff? It's important on the front differential cars to replace the fluid specifically in that, I don't know why it heats up more than the rear one, but I pull 120k 75w90 pretty routinely from the rear and it looks new ish, but the front diffs are always trashed oil that smells particularly awful, I think the amount of sulfur in the anti wear additives cooks off and makes it smell that way but yeah it's usually cooked. The newer 4matic E63S thankfull have a published interval so those owners should be ok.
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Joined: Jun 2022
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From: WA State, USA
2014 Cummins, 2014 E250 Bluetec
More than likely the reason its cooked is because its a small amount, right next to the engine, and the under floor protective covers (not sure what to call them) prevent good airflow in that area from the looks of it. Realistically that should be a couple of quarts (atleast) capacity with decent airflow to keep temps down.
