Transmission Shaft Lip Seal Leak

[leepoffaith]

I have a leak coming from my transmission and I think it's coming from the lip seal on the main transmission shaft. Originally I was not sure where the leak was coming from and I had thought I solved it by unclogging the breather port, but unfortunately I was incorrect. :-/ I've attached pictures of the outside of the transmission with the leaking fluid on it as well pictures I took with a camera scope through the hole on the side of the transmission. (I thought it was odd to have a hole in the transmission housing, but there is one on each side an they definitely look like they were manufactured like that) The pictures with the scope are a little hard to determine at first, but the main part in the middle is a new throw-out bearing (found out the clutch, pressure plate and throwout bearing were all replaced before I purchased the car). You can see the drip of fluid coming off the main transmission shaft to the left of the bearing. Could anyone confirm that my diagnosis is correct? And if I'm not correct, which could very well be, I'd appreciate suggestions of what it might be.

I also changed the transmission fluid today and included a picture of the old vs. new fluid. It was pretty dirty and I'm not sure when the last time it was changed. I estimate that it had roughly 3.3 quarts of transmission fluid in it. I put 3.7 quarts of 80w90 Valvoline High Performance Gear Oil back into the transmission. It just barely started leaking out of the fill hole when I put the last drop in (not sure if this is normal or if I filled it too full). I drove the car for roughly 45 minutes afterwards and it shifted just fine (although it shifted pretty good with the old oil too). However, now it's leaking way more then it was previously. Before changing the fluid I used to have a small puddle after letting it sit for a day. Now I have the same size puddle after the car sat for 30 minutes. I'm assuming the transmission fluid level had something to do with this?

Any suggestions or help with this would be greatly appreciated. Also, anyone live in the Tampa area that has a car lift and some extra time on your hands?! :) I have a feeling that part of the solution to this problem will be removing the transmission and while I consider myself ambitious I don't think I'm comfortable doing that in my garage with jack stands just yet. I'd be more then happy to assist and reimburse you for your time. Everyone has been extremely helpful here, but I don't expect anyone to work free. As always, thanks in advance for everyone's help and suggestions.

*Two of the fluid leaking pictures are flipped upside down. It doesn't show like that on my computer when I uploaded so I'm not sure how that happened.

[Bitsyncmaster]

Since your leaking more now after you replaced the fluid and topped it off I would guess your leak is transmission fluid and not engine oil. When I did my clutch, I found the drivers side cam plate on that head was leaking oil. I did have a small drip after a drive and did not know if it was engine oil or transmission fluid. I have not driven the car much since I did the clutch so not sure if it was that cam plate.

[David T]

Check that it is not the clutch slave cylinder leaking. Have you checked the level in the clutch reservoir? A lift is great to work on but to do the transmission on a lift you will need a transmission jack. If you do remove the transmission figure on replacing the clutch if it is oil soaked.

[DMC-81]

Lee, can you pinpoint the area where it is dripping from? There is a guide tube that seats up against the lip seal inside the gearbox. The other end of guide tube has a hole in it pointed down, about where the release bearing is. (See pic).

http://dmctalk.org/attachment.php?attachmentid=49700&d=1490139893

If the lip seal is leaking, the gear oil will travel out the tube and mostly drip out of the hole or the end.

There is also an o-ring that seals the other end of the tube against the clutch housing. If this seal has failed (or if the tube has rusted through) the oil will drip from between the tube and the clutch housing. The tube is painted black in the below picture:

http://dmctalk.org/attachment.php?attachmentid=49954&d=1490829465

Either one of these scenarios requires the transmission to be removed and split. If so, there are other seals etc. that you'll want to do "while you are in there".

Here is my refurbishment thread to look at in case it helps:
http://dmctalk.org/showthread.php?14544-5-Speed-gearbox-flaw-repair

[leepoffaith]

Check that it is not the clutch slave cylinder leaking. Have you checked the level in the clutch reservoir? A lift is great to work on but to do the transmission on a lift you will need a transmission jack. If you do remove the transmission figure on replacing the clutch if it is oil soaked.

Hi David!

I'm pretty sure it's not clutch fluid. I've been keeping an eye on the clutch reservoir and it's still full. :-/

[leepoffaith]

Lee, can you pinpoint the area where it is dripping from? There is a guide tube that seats up against the lip seal inside the gearbox. The other end of guide tube has a hole in it pointed down, about where the release bearing is. (See pic).

http://dmctalk.org/attachment.php?attachmentid=49700&d=1490139893

If the lip seal is leaking, the gear oil will travel out the tube and mostly drip out of the hole or the end.

There is also an o-ring that seals the other end of the tube against the clutch housing. If this seal has failed (or if the tube has rusted through) the oil will drip from between the tube and the clutch housing. The tube is painted black in the below picture:

http://dmctalk.org/attachment.php?attachmentid=49954&d=1490829465

Either one of these scenarios requires the transmission to be removed and split. If so, there are other seals etc. that you'll want to do "while you are in there".

Here is my refurbishment thread to look at in case it helps:
http://dmctalk.org/showthread.php?14544-5-Speed-gearbox-flaw-repair

Hi Dana! It could be the guide tube seal as well. It's pretty difficult to figure out exactly where it's coming from. I'm pretty sure it's somewhere on the transmission side of the release bearing, but it's pretty hard to pinpoint. Any tips on how to pinpoint where the leak is? Thanks for the great pictures! I'm going to read through your post on the refurbishment later today. :)

[Nicholas R]

I concur with Dana. I would be suspect of the O-ring more than the lip-seal on the input shaft.

On a side note, are you sure it's not the main seal on the engine? If it starts leaking, it can make quite the mess. With oil on the throwout bearing I agree that it's likely gearbox oil but still, something to consider. A simple smell test should give the answer pretty easily; 80w-90 is pretty hard to mistake given the high sulfer content.

Also, I'd definitely recommend resolving this sooner than later; with that much fluid inside your bellhousing, you're going to see your clutch start slipping pretty soon. I had to replace a kevlar clutch disc a couple months ago for the same reason (oil on the disc). I was pretty upset to see that the disc itself was still in excellent condition with minimal wear. Unfortunately, once it was saturated with oil, there was nothing that could be done to save it.

[leepoffaith]

I concur with Dana. I would be suspect of the O-ring more than the lip-seal on the input shaft.

On a side note, are you sure it's not the main seal on the engine? If it starts leaking, it can make quite the mess. With oil on the throwout bearing I agree that it's likely gearbox oil but still, something to consider. A simple smell test should give the answer pretty easily; 80w-90 is pretty hard to mistake given the high sulfer content.

Also, I'd definitely recommend resolving this sooner than later; with that much fluid inside your bellhousing, you're going to see your clutch start slipping pretty soon. I had to replace a kevlar clutch disc a couple months ago for the same reason (oil on the disc). I was pretty upset to see that the disc itself was still in excellent condition with minimal wear. Unfortunately, once it was saturated with oil, there was nothing that could be done to save it.

Nicholas,

I'm 99% sure it's not engine oil. I've never smelled Gear Oil before, but now that I have the smell is unmistakable. I agree i need to get this taken care of ASAP. The clutch, release bearing and pressure plate are all brand new (Less then 2,000 miles on them) and the last thing I want to do is have to spend more money to replace all of them. Currently the clutch is gripping great, but I have noticed after driving it for a while that it seems like the clutch engages later then it did when it was cold. I'm assuming this is because it gets wet from the gear oil and starts to slip a little. Do you think it's bad enough where I'd have to replace to clutch as of now?

[Nicholas R]

Do you know if your clutch line is the original plastic style, or the newer braided stainless style? It's the hose that runs from the master cylinder to the junction on top of the transmission (where it changes to a solid line). Item 11 on this page: http://store.delorean.com/c-384-4-4-1-clutch-hydraulics.aspx

It's very common that the original plastic lines will begin to degrade over time and actually start to expand when heated. This means that when you press the clutch, some of the pedal throw is simply being used expanding the line instead of disengaging the pressure plate (causing the clutch to disengage later, or not at all). Its an easy fix, just replace the line with the newer stainless steel braided line. All the vendors sell them. I'd lean toward this over oil on the disc.

When my clutch had oil on it, it didn't matter what I did, it slipped all the time no matter if the pedal was pressed or not, and regardless of whether the engine was cold or hot. Nothing like being on an on ramp trying to get up to speed, and seeing your tachometer going up with your speedometer staying the same.

[dn010]

This is the second time I've driven with an oil soaked clutch disc. The first time the disc was soaked with gear oil and as Nicholas said it slipped all the time. This time it slips badly when I try to take off from a stop and then it seems to be fine once I'm going. This second time the issue was a leaky clutch slave cylinder, my guess is it's not enough fluid to soak the disc and make it constantly slip but enough to make it slip when taking off. The cylinder was replaced but I have yet to change the clutch, maybe with the upcoming holidays I'll be able to get it done.

If you're unsure of what kind of fluid it is, smell the old gear oil or gear oil container and compare it. You can also put some engine oil from the dipstick on your finger to see if it's closer to that.

[leepoffaith]

Do you know if your clutch line is the original plastic style, or the newer braided stainless style? It's the hose that runs from the master cylinder to the junction on top of the transmission (where it changes to a solid line). Item 11 on this page: http://store.delorean.com/c-384-4-4-1-clutch-hydraulics.aspx

It's very common that the original plastic lines will begin to degrade over time and actually start to expand when heated. This means that when you press the clutch, some of the pedal throw is simply being used expanding the line instead of disengaging the pressure plate (causing the clutch to disengage later, or not at all). Its an easy fix, just replace the line with the newer stainless steel braided line. All the vendors sell them. I'd lean toward this over oil on the disc.

When my clutch had oil on it, it didn't matter what I did, it slipped all the time no matter if the pedal was pressed or not, and regardless of whether the engine was cold or hot. Nothing like being on an on ramp trying to get up to speed, and seeing your tachometer going up with your speedometer staying the same.

The clutch line is braided stainless. That was replaced as well. There were a lot of updates/ parts replaced on the car which is a good thing. I think this trans fluid leak is a fluke, because other then that and a oil pressure sensor that leaks ever so slightly everything else mechanically with the car is really good. I know the master cylinder and clutch line are both brand new. It looks like the slave cylinder is still original but there is no fluid coming out of that.

[dn010]

What does your engine oil look like? How about coolant? It's just weird that it's a rust color. Maybe a coolant hose has a slow drip back there.

[leepoffaith]

What does your engine oil look like? How about coolant? It's just weird that it's a rust color. Maybe a coolant hose has a slow drip back there.

Engine oil has been steady the past two weeks. It has a tiny leak from the oil pressure sensor but not even enough to drip on the ground. Coolant is good as well. I agree the color is odd, so I struggled with what it was, but the smell definitely indicates gear oil. Also, now that I changed the gear oil yesterday the new leak looks identical to the oil I put in so I'm 100% sure it's transmission fluid.

[David T]

If you are convinced it is gear oil then just pull the transmission and reseal it. If it is not leaking badly just put a pan under the car in the garage. An occasional drip of something from an old car is to be expected unless you are fanatical about it. Even if you manage to stop every leak it will start leaking from somewhere. It is safe to tolerate some leaks. There can be NO leaks from the brakes, the clutch hydraulics, and the fuel system.

[leepoffaith]

If you are convinced it is gear oil then just pull the transmission and reseal it. If it is not leaking badly just put a pan under the car in the garage. An occasional drip of something from an old car is to be expected unless you are fanatical about it. Even if you manage to stop every leak it will start leaking from somewhere. It is safe to tolerate some leaks. There can be NO leaks from the brakes, the clutch hydraulics, and the fuel system.

David,

While it might sound easy for you, pulling the transmission is a huge job for me. :-/ I have been extremely fortunate to have a fellow forum member offer to help me do this so I think it might be possible, but without his assistance doing this project on my own would not be possible. I agree a transmission fluid leak in and of itself isn't that big of a deal and I'm not worried about fluid on my garage floor, but I was concerned that the fluid may saturate the clutch and/or release bearing causing more costly repairs. If this weren't a concern I'd just let it leak until I could figure something out. :) I do have a small oil leak from my oil pressure sensor and while it's on my "to do" list, it doesn't really bother me as long as my oil level stay at an acceptable level.

[dn010]

Depending when and where I may be able to help too. Unfortunately I've had to do some work inside my transmission and had it open a few times.