Main seal leak

[Jonathan]

What can you tell me about a main seal leak? I suspect this sums up where my oil drip is coming from and wanted to learn what I'm in for in terms of fixing it, ignoring it , monitoring it, etc.

From what I can see, there appears to be some consistency with drips coming from what looks like the cross member going under the engine. More toward the front of the car though. I got under there detailing not long ago and it seemed like there was oil coming from inside the frame at the time. If I look at the front of that frame section, looking towards the rear of the car, it is pretty filthy. I have gotten a pretty good handle on other leaks and fixing those (rear axles, oil sender-light, and ATF in a few different spots). What continues to drip looks to come from this location where the engine meets the trans, and right above the frontside of that rear frame cross member.

So, for monitoring it, is the source ultimately the engine oil volume? Or is this going to be partly gear oil too? Engine oil can be checked easily, gear oil not so much.

What is involved in fixing this and how far out of a DIY car guy's hands is this? It isn't like it is pouring oil, but after getting my other leaks sorted out, this is the only one remaining. I can leave it just as it is if it isn't going to cause some sort of awful failure down the road. Just trying to see about what my options are.

[DMCMW Dave]

What can you tell me about a main seal leak? I suspect this sums up where my oil drip is coming from and wanted to learn what I'm in for in terms of fixing it, ignoring it , monitoring it, etc.
.

-remove axles
-remove transmission
-remove clutch and flywheel
-remove seal retainer plate
-replace seal and retainer plate gasket
-assemble

[David T]

-remove axles
-remove transmission
-remove clutch and flywheel
-remove seal retainer plate
-replace seal and retainer plate gasket
-assemble

Unless it is leaking badly most people would just wait until it is time to replace the clutch and deal with it then. In the meantime monitor the oil level in the motor and do NOT overfill it, keep it midway between full and low.

[Jonathan]

-remove axles
-remove transmission
-remove clutch and flywheel
-remove seal retainer plate
-replace seal and retainer plate gasket
-assemble

Yuck. I think the step for me before "remove axles" would be "find another hobby."


Unless it is leaking badly most people would just wait until it is time to replace the clutch and deal with it then. In the meantime monitor the oil level in the motor and do NOT overfill it, keep it midway between full and low.

This I like. It isn't leaking badly so monitoring is fine with me. 20,000 drops per litre by the culinary measurements... I got time.

[DMC-81]

I think the transmission removal takes it out of the DIY realm for most people, unless you have a lift and a helper. Unfortunately, it will only get worse. I saw a car at a tech session that had a nasty leak from that seal. Definitely keep an eye on it.

In case you need it, the Delorean episode (S08,E07?) of "Wheeler Dealers" showed the main seal replacement quite well. I think the episode is on YouTube.

Cheers,

[chris williams]

Unless it is leaking badly most people would just wait until it is time to replace the clutch and deal with it then
Mines been leaking for about 3 years now, one of those jobs I keep putting off. Other than leaving a small puddle when parked after a long drive there are no major issues. I suppose it may be getting on to the clutch plate but I would change that whilst in there anyway.
Chris

[David T]

I think the transmission removal takes it out of the DIY realm for most people, unless you have a lift and a helper. Unfortunately, it will only get worse. I saw a car at a tech session that had a nasty leak from that seal. Definitely keep an eye on it.

In case you need it, the Delorean episode (S08,E07?) of "Wheeler Dealers" showed the main seal replacement quite well. I think the episode is on YouTube.

Cheers,

I have done them with just a floor jack and alone but a helper is a good idea and a lift is a luxury. If you do use a lift you will also need a transmission jack because it is heavy and over your head. I agree it is not a novice job but novices have done it. A lot depends on how financially motivated you are. I get surprised at how resourceful some people can be. Now with Youtube there are a lot of people who will see it and try it. You don't need a bunch of special tools either except for the alignment tool. If you have a friend who is mechanically literate it can be done in an afternoon. I would figure longer because of all of the "While you are in there" kind of other things. For instance I would replace the clutch slave cylinder, the roll pins in the transmission, the output seals (if they leak), shift linkage bushings, motor mounts, maybe grinding the flywheel and anything else that is found to be worn. Hey, how do you know when a British car needs it's oil checked? Answer: When it stops dripping! As for it getting on the clutch, the clutch is on the other side of the flywheel. The drip won't affect the clutch but it does make the job a lot messier.

[Timebender]

My main seal is leaking as well. Sometimes a little puddle, sometimes a bigger one. When I first got the car, there was a pretty good leak in the back, so I sent it to Danny, and they replaced the clutch slave as he said that was where the most leak was coming from, and my valve cover gaskets. I eventually did those on my own as the car has a Chevy 350 small block and that's an easy job. But it kept leaking. One of my neighbors is a mechanic, has the engine lift, and he and his buddy who work a lot on 350's did say it's the main seal, but the job would mean taking off the facia (easy), unbolting the engine and disconnect stuff (easy), take it out (easy), replace the two parts of the seal, then reverse that order.

Or do we need to do all that other stuff as well (axles, etc. etc. etc.)?

And how hard is it to remove the transmission, and does it really need to come out? And if we remove the axles and trans, then what do we use to keep the car off the ground?

Greg

[vps3922]

I think the transmission removal takes it out of the DIY realm for most people, unless you have a lift and a helper. Unfortunately, it will only get worse. I saw a car at a tech session that had a nasty leak from that seal. Definitely keep an eye on it.

In case you need it, the Delorean episode (S08,E07?) of "Wheeler Dealers" showed the main seal replacement quite well. I think the episode is on YouTube.

Cheers,

It is:
https://www.youtube.com/watch?v=8JOnKd90kYE

He is starting around 16:40 into the episode.

[Timebender]

Can't that be done as easily by just pulling the engine out?

[Jonathan]

How much of the mentions of the clutch and transmission change for me because my car is an automatic? I don't have a master or slave cylinder, but the rest I wasn't sure about it being common to both types of trannys.

[David T]

How much of the mentions of the clutch and transmission change for me because my car is an automatic? I don't have a master or slave cylinder, but the rest I wasn't sure about it being common to both types of trannys.

If you are only going for the clutch and/or the crank seal IMHO it is easier to only pull the transmission. There are not very many reasons to pull the motor. Pulling the automatic just means it is a little heavier and you won't need an alignment tool. Less while you are in there stuff but I would clean the filter and change the fluids and replace the converter seal. Before doing this job see how much oil is in the final drive. Maybe that is what you are seeing drip, NOT the engine seal.

[Jonathan]

I think the transmission removal takes it out of the DIY realm for most people, unless you have a lift and a helper. Unfortunately, it will only get worse. I saw a car at a tech session that had a nasty leak from that seal. Definitely keep an eye on it.

In case you need it, the Delorean episode (S08,E07?) of "Wheeler Dealers" showed the main seal replacement quite well. I think the episode is on YouTube.

Cheers,


It is:
https://www.youtube.com/watch?v=8JOnKd90kYE

He is starting around 16:40 into the episode.

Thanks for the link.

When I watched the section on the rear seal replacement, they mentioned losing the oil out of the "gearbox." Realizing mine is an automatic, is this leaking oil going to be exclusively from the final drive? i.e. gear oil and NOT engine oil? I can't quite visualize what is on either side of that seal.

[DMC5180]

Jonathan,

It's probably a good idea for you to familiarize yourself with the 3 distinctly different oils in your car. Smell is probably the best way I know of when determining the source of what is leaking. ATF, gear oil (final drive) and engine oil have unique odors. Of coarse ATF is Red or reddish brown if old. Gear oil has a strong pungent odor. That leaves motor oil.