140 differential - PeachParts Mercedes-Benz Forum

jayhawk · #1 12-04-2002, 07:49 AM

What interval does the differential oil need to be changed in an s320? Looking at the maintenance schedule, I do not see where it is scheduled for change.

savagetom · #2 12-04-2002, 03:33 PM

I don't think there is a specified interval. I changed mine to Mobil synthetic at 90M maintenance work.

jayhawk · #3 12-04-2002, 04:26 PM

Did you do it yourself? Any tips for a DIYer?

#4 12-04-2002, 07:31 PM

I don't know if all Mercedes have it but mine have had a vent that screws into the top of the differential. This can get dirty and/or clogged up.

Some are hard to remove and some are not but it's a good idea to check it and clean it if possible. One MB technician told me he squirts some sort of cleaner on it if he can't remove it.

Mercedes (in the past) has only included a check for level of the differential lube in their service recommendations. On the other hand, BMW recommends replacing the lube at specified intervals which is what I do on both my Mercedes and BMW's..

savagetom · #5 12-04-2002, 09:24 PM

Bud, do you know what BMW's service interval is for the differential lube.

As for tips, the classic is to remove the fill plug before removing the drain plug. If the fill plug is stuck then you can retreat and fight another day as long a there is fluid in the differential.

You can get the 14mm (I think) hex socket that you need at Autozone in a set of three for about $10.

You'll need a short piece of tubing to stick in the fill hole and on the bottle of lube.

Be sure to use jack stands when under the vehicle. You may have to lean on the wrench pretty hard. Make sure the wheels are chocked.

Good luck.

#6 12-04-2002, 09:32 PM

My BMW's had a 30K interval and that's what I use with my Mercedes. BTW, I also use Mobil 1 in the differential (as well as the engine and transmission).

savagetom · #7 12-04-2002, 10:49 PM

Wow, 30M! Seems pretty frequent. I wonder if there are differences in design, fluid capacity, etc. that would explain the apparent fill-for-life approach of MB versus the 30M approach of BMW.

#8 12-04-2002, 11:13 PM

That was 30,000 miles. Now that BMW pays for maintenance for the first 4 years on 2003 models, they probably don't change it as often as they used to.

It probably doesn't need to be changed at 30K intervals but I look at it like spark plugs. If you're going to go to the trouble to check it why not just replace it since lube (and copper plugs) are so cheap?

md21722 · #9 12-05-2002, 11:12 AM

Service interval for M-B differentials has been every 30,000 miles forever, unless they lengthened that interval recently.

oldsouth · #10 12-05-2002, 12:59 PM

I dosn't say in the owners manual but the dealer changed mine at the first free oil change. After about 50,000 miles I changed it to Mobil Synthetic 75-140 gear oil and now change it every 100,000 miles. That oil is reccommended in big trucks for a 500,000 mile interval.