Last week I had the oil and differential fluid changed on my '84 380SL. Yesterday I noticed that the differential had a leak that was dropping oil (about the size of a quarter) on the floor of my garage. After looking at the bill I noticed that the tech had put limited slip oil in the diff. I don't think that my car has one and so my question is twofold.

A) Is the leak perhaps due to the different fluid?

B) Can I stop the leak by just changing back to the regular fluid or am I in for a big bucks repair?

Most of the 126 cars I've seen use a 14mm allen head socket to remove the drain/fill plugs on the differentials.

Auto Zone sells a 3 piece set(12mm/14mm/17mm) for around $10. I'd get underneath and check just how snug these two 14mm plugs are.

I don't know if yours requires gear oil that supports limited slip operations, but either way, I'd doubt that would cause a leak. I've used Valvoline semi-synthetic in my 126 for the past 5 yrs. with no problem.

My 2 cents.

The type of oil used is not a factor in the leaking.
3 possible sources:
1) 'Residual' dripping from messy job (mechanic did not cleanup oil spilled on outside of diff).
2) Leak around fill or drain plug (not installed tight enough).
3) Leak around cover gasket (mechanic may have removed this to inspect gears)

Try this:
Clean the diff with spray brake cleaner, then let it sit a while.
You should then be able to determine where the leak originates.

__________________
1986 300E 5-Speed 240k mi.

The problem turned out to be that the instant oil change place did not replace the washer on the drain plug. I had to have the dealer do it at a cost of $70! I'm now fighting with the company that franchises the oil change place.

Pray for me!

The moral to all of this is DO NOT take your Mercedes-Benz to an instant oil change place![SIZE=4][SIZE=4]

$70.00 for a washer, WOW !!!!!

I think I'll go into the washer changing business.
Lets see, could do a hundred MB's a day hmmm.maybe I can buy that unimog motorhome afterall.
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