My rear end seal is leaking badly so I was going to take the cover off and change the oil (it probably has never been done) while I was at it. The dealership told me there isn't a MB gasket sealing the cover to the housing. They said to use RTV. That just sounded strange to me. Is this correct?

Scott

'85 300D 190k

Yep, it sounds strange. Yep, it's the right procedure. Also, loosen the FILL plug first to make sure you can get fluid back in when you're finished.

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Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
Chain Elongation References

IF they are correct I suggest these things...
1. take the fill plug out first and while the cover is on the car.
2. take the drain plug out while the cover is on the car and before you take the cover off ( you will be much cleaner that way )
3. Drain at least overnight
4. Wipe it out completely with a rag so no fluid will be dripping on the edge of the surface you are going to put the RTV on....
5. Clean the sealing surfaces with Lacquer Thinner or Berryman Chemtool .... keep using clean rags or paper towels until it is still clean after you wipe it.
6. use your finger and put as thin a coat of RTV on each sealing surface as you can and let sit overnight.
7. When you start to put it together use your finger again and put a thin coat of RTV on each item.
8. Put them together within 5 minutes of number 7 above , ie, before it starts to ' skin'...
9. Treat the tightening sequence like you would a wheel.... a star pattern.
10. Do not overtighten. That is the biggest cause of gasket failures .... by far ...

I have never had a seal fail when doing this .... in 30 years....I think I saw this suggested on the side of an RTV tube....

Thomaspin documented this procedure. It's in his website.

Sixto
91 300SE
87 300SDL
83 300SD

When Thomaspin has documented everything are we going to be reduced to just saying " go look at " his site ? I will have to take up some other sport ....

I'll get a BMW

Sixto
91 300SE
87 300SDL
83 300SD

Thanks for all of the responses so far. I have just one more question: What are the torque specs (in pounds preferably) for the bolts?

Scott

45Nm which is 33lbft. No sequence or pattern is given. I'd do every third bolt clockwise in 2 or 3 stages.

Sixto
91 300SE
87 300SDL
83 300SD

leathermang,

Would the same technique be used on a '88 300E? The diff. appears to be leaking from the cover plate seal. I was not sure if there was a gasket or not.

Marks88

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'88 300 sold
'83 300cd

That is my technique for anytime RTV needs to be used... it makes sure there is good contact on all the surfaces and minimizes the amount of RTV which is squishing... so you don't get loose RTV inside the item...If it DOES have a gasket just treat the surfaces of it like you have four surfaces you are dealing with instead of two....
For places that use cork gaskets... coating them like this really makes them work well... they have the bouncyness to stay seal and this seals them up....