amanonfire

Has anyone noticed the rear differential leaking?

I have 160K kms (100K miles) on my car and noticed a slight leak from one side. Going to monitor it to see how much its leaking.

Not worth repairing, yet I'll keep the diff topped up with oil from now on.

How do you inspect the oil level in the diff?

bumpnzx3

never looked at it- but i would assume there is a threaded plug (hex or allen head) about half way up the diff. fill to the bottom of that threaded hole. if the threaded plug is on the top of the diff- fill to approximately half full. i would also assume that there is a similar threaded plug on the bottom of the diff to act as a drain plug. again- not positive that's how it is, but that's more or less standard practice on any other diff i have worked with.

amanonfire

There is a huge threaded plug on the bottom passenger side to drain, I didn't immediately see a fill hole.

If its on top that would suck since there's no easy access.

bumpnzx3

once the car is lifted up via a jack- the suspension should drop down enough to get to the plug with relative ease. i couldn't imagine them designing it in such a manner that the rear end needed to be dropped in order to perform a simple maint. task.

on a side note- for some reason i think i remember seeing a DIY on a rear diff lube. i will have to see if i can find the thread.

bumpnzx3

C230 Sport Coupe FTW https://mbworld.org/forums/showthrea...d+differential

Glyn M Ruck

Make sure car is level when checking level & pop in a new seal unless it's only a very slight weep or it will let you down when you least expect it.

amanonfire

It seems to be a slight leak right now, yet obviously it could get way worse at any moment.

Pop in a new seal?
How easy is it to change the diff seals?

I read it is a $500 job to do both. Since its only 1 seal I'm going to get a quote this week.

amanonfire

5 hrs labour and $100 in parts/fluids

The seals on the stock diff suck, they fell apart when removed. Hopefully these seals are better, or else I'll be doing this again in 160K kms.

Glyn M Ruck

Good - you got it done - I think you are wise - I know 5 hours is a sweat but you saved big bucks

phoenix_iii

Trying to determine if I should pay the dealer the ~$600 to do this. Could it go from slow to all gone quickly? Wouldn't one hear the diff whining at highway speeds, etc?

Mine is leaking (2 of 3 seals I believe I was told). I was thinking of just topping it off and monitoring.... but Glyn says bad idea?

Xhale707

14MM hex Bolt
On the bottom right is the drain plug..
Left side on the top is the fill plug..

Remove the fill plug first then the drain plug

So easy

And so only 20 dollars for the whole job

govertime

i believe Phoenix is inquiring about replacing the seals, not replacing the fluid itself.

Xhale707

Yeah its there if he doesn't know k thx

Glyn M Ruck

Phoenix. The trouble is that it's not going to get any better. You might get away with a regular top up for a while but it could let you down when you least expect it & then you loose a diff. Diffs unfortunately will not go very far before failing with very low or no oil. Once you hear noise it's all over. Can't you get an Indy to do the job more reasonably.

Good luck!

phoenix_iii

When I spoke to my SA about deferring it and just topping it off, he said that would be okay. I also asked if he ever heard about a diff just failing (seals going from slow to GONE, etc) and he said no. I trust Glyn's opinion more.

Is there 'nothing to it' in terms of replacing the diff seals? If I supply the MB parts, is it something to trust to an indy shop?

I am also thinking of parting ways with car (need money for legal matters), so I am not sure if it is best for me to do this or the possible new owner.

Glyn M Ruck

Indy shop should have no problem. It's not difficult - Just a little time consuming.

phoenix_iii

Good to know. I still get that disconcerting 'thumb' from what feels like the differential on moderate stops, doesn't do it all the time, and better since I replaced the transmission mount.... so we'll see if topping off helps.

briankc86

What exactly is the differential seal called, like when I'm looking for it on AutoZone's, O'reilly's or Advance Auto's websites?

Is it difficult to change? Or is it as simple as removing a sort of "cap" and replacing the old seal and reassembling?

~Brian

capt_paul

I don't think you are going to find those seals at a generic auto parts place.

briankc86

I noticed some oil/grease on the garage floor where the rear end would be if the car were in the garage. I got under the car and took a glance and found the leak. Mine appears to be leaking from where the cover seals with the rear end.

It's my understanding the dealer likes to reseal the entire rear end at once. That's probably the right thing to do, but I'm wondering if I could just reseal what is leaking myself, at home. The cover looks fairly simple to remove, I'm assuming there's a seal there? What's the difference between a "seal" and gasket. The biggest problem is I don't have a torque wrench and can only tighten bolts by hand.

Hmm.....

Star Rider

Not sure on the Benz since I have not had the pleasure doing that job yet, but, in my experience with other makes there may or may not be a gasket on the rear diff cover. I prefer to use a gasket, but I have also used "gasket maker" in the tube(permatex, etc.) and it works fine. Just be sure to clean or scrape any old gasket material off, clean it well and re-seal it up. I would see if you can find the correct torque setting for the bolts and tighten them in a star pattern similar to lug nuts on a wheel.

Glyn M Ruck

Use Yamabond 5 or 6 on that back plate. Permatex is crap.

Star Rider

I have never heard of Yamabond. Is it available in the states?

Glyn M Ruck

Yes indeed. The global racing fraternity including F1 survive on the stuff. Designed by Yamaha for aluminium engine & gearbox casings where no gaskets are used & vibration & some movement might be present. It's a pleasure to use. It works brilliantly & is easy to remove if you split the joint. Available from Yamaha dealers & online.

johnand

+1. I have to thank Glyn for pointing me in the direction of Yamabond for a oil pan leak I could never seal on my Jeep. The stuff is fantastic!