I want to change the differential oil in my wife's 95 E320 wagon. There is no way I am getting under there without raising the car up (I have no lift and no pit). So the question - Does the car need to be level to do the drain and fill? It seems to me it should be but if I raise on jacks in the back, it will be tilted forward. I was thinking to run the front up on ramps and jack the rear. This makes me nervous the more jacking I have to do so wondering what other folks have done or does anyone even worry about this? I am guessing most folks don't worry about this but I can't see how the fill level will be right without having it level.

Refill with the recommended amount of oil. That information is in the owners manual.
The car deosn't need to be level.

Jack it up on one side and get a jack stand under it, then see if you can get the fill plug off first thing. If not then stop right there.

If the fill plug comes off then you can remove the drain plug, drain the fluid and replace that plug. Set the car down then fill it back up until it starts draining out the fill hole and replace that plug. Not a lot of room to work and pump the fluid in but that's what I did.

You'll need a 14 mm Allen wrench for the plugs. You may want to use Teflon sealant or Teflon tape on the plugs to prevent leakage.

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1993 400E, 256,000 miles (totaled)
1994 E420, 200,000+ miles
1995 E420, 201,000 miles