Rear main seal, what else?
 

Did an oil change yesterday to notice some oil leaking from where the engine meets the transmission.. My guess is that the rear main seal is going out and it's only going to get worse since I daily drive my 55. I recently did the valve cover gaskets and apparently it is pretty common for the rear main to go after you do the VCG's..

My question is, is there anything else that should be done while that area is accessible when replacing the rear main seal? I'm already due for a transmission flush, filter, fluid change and plan on replacing the 13 pin connector too. What else should be done as preventative maintenance?

Also, how much do the stealerships and indy's normally charge to do that kind of work?

Find an Indy, should be 300-500.

I just did the rear main seal, valve cover, tranny pin, filter/flush. A couple weeks later, my tranny oil pump decided to break down and left me stranded on the side of the road. I would check into this, since common part to break down. Also got the conductor plate for tranny replaced as well. Might as well get that done with the tranny dropped from the car. With car in the shop, also drained/filled the rear differential, and engine oil change.

$300-500 seems low to me.
The tramsmission needs to come out, gotta be a full days job, no?

Reason it takes long is because the seal has to cure and it's on the lift waiting

Hello,,anyone possibly knows the part nr of the rear main seal?

I don't remember any curing time when we did my rear main seal. Not sure if I regret it. Because within 2 years it started to leak again.

My new 06 motor had no leaks. But, my indy convinced me to change the rear main. I remember he said he did not want to remove the plate but instead just swap the seal. I didn't get that. Why wouldn't he just unbolt the plate and swap the rear main seal.

I was unaware of this curing time as well, care to elaborate? I believe the seal and plate come together as one part, I think I paid like $18 plus around $500 in labor, which included the transmission and engine mounts.

Right, the rear main seal is just a big round seal, I don't believe there is any sealant used. But, I could be completely wrong. I just remember that.

Well my indy guy did not purchase a new aluminum piece with seal. Just the seal by itself. I'm curious if that was the issue for the leak coming back so quick?

Or is it normal for the rear main seal to leak that quickly? I suppose releiveing crank case pressure will help with this. Maybe a catch tank will help resolve this?

Could be Tranny oil pump! make sure it's motor oil not ATF oil.

the rear main seal is separete from the rear plate. They are sold differently, not together.

Per mb orginal WIS instuctions the plate should be changed with the new seal. Also when istalling the new seal the WIS states not to use any kind of lubricant on the sealing surface of the crank or the seal itself.

So the back plate is secured with bolts and sealant, and the rear main seal is just pushed on to it

Edit: there is a cure time.. cant remember but it was pretty long!

https://cimg3.ibsrv.net/gimg/www.mbw...526c546514.jpg

https://cimg4.ibsrv.net/gimg/www.mbw...9977ff33fd.jpg

https://cimg5.ibsrv.net/gimg/www.mbw...b1e7c270e1.jpg

The longer the better, problem is that they charge for the cure time that they are not working on it :(

Go to a good Indy and he will take care of you

Change the motor mounts.

Ohhh Now I get what you mean by cure time. It's fore the sealant around the plate that bolts on. I thought you meant cure time for sliding in a new rear main seal. I was like huh? Haha :p:

Darn, my indy guy didn't swap the plate. He just R/I the old rear main seal with a new one. Maybe that is why it's starting to leak again. It would have been better if I left it alone until it needed replacing. :smash: :smash:

Now I am tempted to drop the trans and replace it again. But, is a new plate really necessary? Cant you just clean off sealant residue and reseal and install with new seal? Or is the plate a one time use? What about the screws?

Anyone know? :y

Great pics thank you. No lubricant used other then a very light coat of engine oil to the crank edge so the seal doesn't drag and flip inside out. Mine was changed 2 years ago. But, just the seal plate was left in place. :hammer:

Now it's starting to leak a little bit. Looked like engine oil. Not trans oil thankfully.

The new plate is probaby around 30to60usd, here it was around 30 eur so just swap it out.. cant really tell if its bc the plate not being swiched or that engine oil around the crank thats causing it to leak again but WIS says to install it completly dry, it didnt make any sense to me eighter but thats how i did it.

How long has it lasted? Do rear main seals leak often on these cars?

When I bought the car it was leaking so I had it done maybe 2-3 weeks later. 3 years later and nothing is leaking. The Indy I went to let it cure over night iirc

get the higher stall converter... wish I would have thought of that when I had my rear main seal done :o

I'd say most of the time it's actually the plate leaking because of the old sealant rather than the actual seal leaking. Cheap insurance to always replace both since taking the trans out to do it is no quick job. Yes the rear main is extremely common on higher mileage/aged m112/m113 engines. Also from my experience no need to worry about a cure time since you still have to install the transmission and everything else and by that time it's cured enough.

I know Rear Main Seals are common on benzes but could someone explain what they are and what the long term damage of not repairing it is? I understand it but not enough to actually understand it

Curing time? You are joking right? This must be some indie riddle. Have changed sooooo many rear mains on the 112/113 motors, never have i ever let it "cure". There is a sealant path that needs to be followed and a special tool to install seal. Job pays 10-12 hours depending on 4matic or not, so in your case 10 hours.

Pulling the transmission is a joke-It isn't even the long part of the job. Cleaning the area of the seal plate is what takes forever, especially the lower corners....
Seal is used to lubricate crankshaft ends, you have a front and rear main seal. Above poster is correct-it is in fact the sealant that goes bad first, usually.

The only reason it would leak after being replace is install/cleaning error. If it takes 10 years for it to leak from the factory, it surely isn't product defect. If cleaned correctly and thoroughly, and correct sealant path used-there shouldn't be any leaks no time soon after repairs.

The white plastic circular disc in the photo btw is not your install tool-be careful for you DIY's, you can easily roll this seal and have to redo the whole job again-and you wont know until the thing is running at operating temperature.

Things I recommend changing to my customers if not changed previously.
1. motor/trans mount
2. transmission connector
3. shifter bushings with new clips
4. hardware/brackets that attach exhaust to trans body
5. replace your indie shop if he only replaces the seal-dumb ahsss-ahhssshole move

Yes rear mains leaking on this generation motor are extremely common. v6 or v8 na or fi...
No real common damage will happen, not to say something can't, but mostly you will just have to add oil ever so often...



Lastly-DO NOT RE-USE THE BOLTS FROM THE OLD PLATE!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Only two should be re-used and those are the super long ones coming from the bottom of the bell housing.....

this is a 3 hour job if he or she knows what they are doing. Usually their level of experience will determine the cost. I personally would do these all day for 500$ plus parts, however I don't own my own business and don't have employees to pay so it'll be more usually whichever shop you go to unless you know someone who will do it for the low on the side....

Good luck!

I have had oil consumption issues lately and the color and smell to me indicates motor oil. I'll most likely have the pump done as well when it comes time to doing the rear main

How do you keep from rolling the seal? Especially installing dry?

You're up on a lift and the drive shaft is out so might be a good opportunity to replace the flex discs on the shaft if they look at all suspicious, also if you are thinking of doing any exhaust mods now is a good time...GL with the seal replacement...