Rear Main Seal Replacement

[belize1334]

So I've noticed a bunch of nasty black oil coming out of my bell-housing (specifically the clutch fork window) and it coincided with my oil consumption increasing significantly which tells me my rear main seal took a dump on me.

I'm going to pull the transmission this weekend to see if that is indeed what is wrong but assuming that it is I have a few questions. Mainly, is there anything that I need other than the seal? Will I have to replace some kind of paper gasket as well? I plan on doing it with the engine in. Are there any tips that people know of or snags that I can expect to run into?

 

[Barnes]

You will have to pull the oil pan. (Well, I would anyways, but that's me.) You might be able to sneak by without pulling it.

You will also need the paper gasket that goes between the main seal bracket and the block.

Can't really think of anything else.

 

[GreenGSX]

Make sure you pull the tin between the transmission and the block. There is a oil galley plug in the 2 o'clock position that can leak. It would be shame to go through all that work and miss that too. If it is leaking you might want to JB weld that back into place.

 

[belize1334]

^^ I'm confused. You're saying 2:00 position on the block or in the bell housing?

Also, I ordered the rear main seal bracket gasket from the stealership but I've heard reports of people doing the job by just prying the seal out and gently pounding a new one into place. The advantage of course is that you don't have to drop the oil pan. Does anyone have experience with or comments about this method?

 

If you have the option of the full bracket use it. I have been a mechanic of a couple of years and have tried both ways, 9 out of 10 when you just press in a new seal and not change the bracket the rear main will still leak. I had a Jetta come back 3 times (had to also replace the clutch 3 times as well) before the customer would pay for the 80 dollar bracket and fix the problem.

 

[Terry Posten]

You can't just pry out the seal without removing the 5 bolts and the small plate. It is pressed in from the inside. I also can't see how you will be able to pull the plate without removing the oil pan. I don't think you would be able to get the "pan to plate" gasket surface to seal properly.

The other thing that can happen is that a wear ring will form on the crank shaft and if you press the seal in so that it sits exactly in that groove, it can leak again. The seal can be seated further or not so far into the plate housing to have it ride in a new spot.

 

May as well replace the oil slinger while you're in there. It's a metal piece that sits behind the rear main seal. Only costs like $2.00 from the dealer.

 

[Barnes]

Quoting Terry Posten:
I don't think you would be able to get the "pan to plate" gasket surface to seal properly.



True, I also forgot that that little bracket has alignment dowels on it. So it would really be a bitch to pry it away from the oil pan, and then get it to seal. Oh well.

 

[GreenGSX]

Quoting belize1334:
^^ I'm confused. You're saying 2:00 position on the block or in the bell housing?

Also, I ordered the rear main seal bracket gasket from the stealership but I've heard reports of people doing the job by just prying the seal out and gently pounding a new one into place. The advantage of course is that you don't have to drop the oil pan. Does anyone have experience with or comments about this method?



The oil galley plug is at the 2 o'clock position looking at the end of the crank. When you pull the tin and look at the plug if its at all wet its leaking. You should clean out the plug and threads and JB weld that back in.



I got that photo from a thread on tuners which has many more good photo's along with some good shots of the rear main seal replacment.

click

 

[belize1334]

Quoting UtahGalant:
May as well replace the oil slinger while you're in there. It's a metal piece that sits behind the rear main seal. Only costs like $2.00 from the dealer.



Part number? Will the dealer know what "oil slinger" means?

 

[belize1334]

I did a bit of research and I think I at least now know what an oil slinger is...seems like we're talking about a washer type thing that goes around the crank. But wouldn't I have to pull the crank to install that?

As for dropping the pan, is it as straight forward as it seems or should I be prepared for strangeness?

 

[Vman911]

They also make a rear main seal sleave. After awhile the seal makes a groove on the crank and the sleeve is made to go over the crank to seal it up better. I can find out where my dad got his for his vr4. It was pretty cheap like 6.00 I think. MY dad got the sleave at parts dinosaur its on the last page of mitsu parts.

If you do replace the oil slinger MAKE SURE you put it back the same way you found it. the hole in it goes on the bottom.

 

[belize1334]

I have heard about the spacer for the crank to help it seal. I think you can get them at local parts stores and I'll look into it. As for the oil slinger I'm really confused about where that goes. My understanding is that the seal sits in the bracket which mounts against the block with a gasket...where in there does the oil-slinger sit? I think it's in the picture below from that tuner's thread (sitting under the pliers) but I can't for the life of me imagine how it fits into things.

 

[grocery_getter]

Its the round object in the middle of the 3 round thing. It is to the left of the round plate that is under the pliers.

The one under the pliers is the timing /spacer plate for the front of the crank.

 

[belize1334]

Ok, that makes more sense then. I'll see if I can get one from the dealership but if not I'm just gonna have to be careful with this one and hope not to damage it.

*Edit: Ok, talked to the dealership and they can get it to me freight by tomorrow afternoon for ~$6.00. They have it listed as an OIL SEPERATOR. I also have a pretty good leak from the CAS (replacing the o-ring tomorrow as well) so it's POSSIBLE that oil from there just worked it's way into the bell housing but I'm not getting my hopes up. Anyway, dropping the transmission tonight or tomorrow...lets hope it IS the rear main seal and not an input shaft seal on the transmission.

 

You're right, it's an oil seperator. Been awhile since I've looked it up.

Here's the part number and pic if anyone else wants to know.

Oil seperator: MD040332

 

[3rdstrikedsm]

good article.

 

Back from tha Dead!

I have this problem, because I removed the oil squirters, Blocked the Balance shaft holes, and didn't port the oil pressure relief valve.

I am guessing that from the research I have done that my oil pressure is around 80+ psi.

Hence I have a leak coming out pretty good dripping off the bellhousing.

I thought it was the galley plug at first, so I re-did the job 4 times.

-Once with a new plug

-2nd time teflon the new plug

-3rd time JB weld the plug

-4th time Tap, JB, another new plug.

I never checked the rear main seal, so I think this is what the problem is.

I will update as soon as I get the motivation to pull the trans YET AGAIN.

 

[Brianawd]

Quote:
I am guessing that from the research I have done that my oil pressure is around 80+ psi.



My motor was pegging my 100psi gauge at any thing over 3k. That never once caused a seal to blow out. I have never see a rear,front or any other seal blow out on a 4g63 because of two high of oil pressure.
There is something else going on with your car.

 

[Armitage]

FWIW I used to have a paper felpro oil pan gasket sealed with hylomar and I was able to change the rear main seal without dropping the oil pan and it never leaked in the following 6 years after.