The other day I was doing an inspection underneath my ML320 and noticed a cross-frame member with an oil film on it. I started to become concerned since I thought I had an oil leak somewhere but on further inspection I could not find anything that appeared to be leaking.

The part in question is a rectangular steel cross-member that sits immediately beneath the transaxle. The part has a label with UPC symbols and the word "SAE 90" as this is the lube that should be used. Immediately behind this member are the torsion springs and attached to this member and protruding forward are round steel (approx. 1-1/2 in.) bars on each end.

Is the oil film on this member from the SAE 90 oil? Is this normal? I know that on some early ML's the transfer case has leaked oil but this does not appear to be the case in this instance. Also, the oil film tracks on the round steel members protruding forward of this member.

Possibly just from someone doing an oil change by removing the drain plug. It makes a hell of a mess.

Gilly

So far only the Mercedes dealer and myself have done oil changes. The dealer at FSS intervals and myself in between so that I am still getting oil changed at approx. 5500-6000 mile intervals. I have always used suction method through the dipstick tube and I am pretty sure the the Mercedes dealer also uses this method. I would suppose that if you were not careful when removing the oil filter you may also get some oil down in this location.

As a side issue, what does the label that states SAE 90 on this cross member there for?

I believe it's for the transfer case, could be for the front diff.

Gilly

That grease is usually excess from the front joint of the front driveshaft. MB switched to a different driveshaft vendor for MY00
and these all blew off a little excess grease during the first 10k.
If you look closely at the bottom of the transmission bellhousing and the side of the frame rail, you will see the same grease
tossed everywhere. Some guys have been tricked by this stuff and have removed the trannys thinking they were leaking only to be sorely disapointed. I wouldn't worry.

The label is for the front diff and it lists the gear ratio, vendor,
and needed lubricant.

DR.D

Yes, I checked the bottom of the transmission housing and side of the framerail and the same grease is in these locations also. Glad to hear it is nothing to worry about since, like others, it appeared to be coming from a leaking transmission or transaxle. I wanted to make sure I did not risk burning out something needlessly.

Took my ML320 to my dealer last week. First of all, I am fortunate to have a good dealer service department.

Turns out the oil on the bottom of my ML320 was coming from a leaking seal ring on the transfer case. They replaced the seal and topped off the transfer case oil. Since it was only seeping, the oil level had not yet dropped to a critical level.