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Posted by: engine247 Jun 26 2023, 09:21 AM

Howdy,

I noticed a newish leak under the car. So I clean up the bottom best I could and let it sit for a bit. The leak appears to just seep through the case slowly but consistently. Maybe a defect or small crack? I'm wondering what my options are here? Only solved with a new case or is there a band aid until this can be bundled with other related maintenance?

Cheers.

Posted by: Shivers Jun 26 2023, 09:30 AM

I wrenched motorcycles in the day. The Honda cb 750 had
a bad habit of throwing its chain. The output shaft and sprocket
was a bad design and when the chain went it would bunch up around the sprocket and shatter the case. We used JB Weld to Humpty Dumpty it back together. And it held up.
If it were me I hit it with some sandpaper and put a few layers of J.B. on it. You can have it welded when you have it apart.

Posted by: rjames Jun 26 2023, 09:43 AM

Looks like it's leaking at the output shaft seal.

Posted by: engine247 Jun 26 2023, 09:55 AM

Yeah, I thought it would have been from a seal but there is no trickle down anywhere. You can cleaned it up again and 5 minutes later there is a small drip starting to form right at that spot.

Posted by: rjames Jun 26 2023, 10:34 AM

Are you sure? Where the drip shows is just the lowest point. Areas outlined in yellow look like where gear oil has traveled from (or to).


There's probably a better way to test, but after cleaning it thoroughly, maybe dust the whole area with baby powder or baking soda to rule out a leak elsewhere.

Posted by: technicalninja Jun 26 2023, 11:01 AM

2nd on the JB weld.

Biggest trick is to get the cracked alloy housing clean!

I once repaired a Toyota cylinder head blow out between chambers with JB weld.

The missing section was the size of my little finger between #1 and 2.

I advised customer (a good friend) that it would last 6 minutes...

Long enough to take it to CarMax or another dealer.

It actually lasted 11 months and 16K miles before it shit the bed a second time.

I was shocked!
JB weld as an integral part of two combustion chambers!

Larry (my friend) had won a 7-figure lawsuit by that time, and they just threw the car away...

Posted by: 930cabman Jun 26 2023, 11:17 AM

Also back in the day, ...... no need to explain, but we had a few

about a 1 1/2" diameter hole in a VW water cooled case, oil pump sheared off and wedged between the spinning crank and rear portion of the case.

JB around the hole, 1/8" aluminum plate, more JB and away you go.

CLEAN is the key part of this type of repair, nothing sticks to trans oil

Posted by: ClayPerrine Jun 26 2023, 11:20 AM

There is a known long term issue with porosity in Magnesium alloys.

https://www.sciencedirect.com/science/article/abs/pii/S0142112302000543

"The present work addresses the high cycle fatigue properties of aluminium-containing magnesium alloys produced by high-pressure die-casting and their performance in comparison to similarly produced cast aluminium alloys. A main material defect in high-pressure die-cast components is porosity, which is caused by microshrinkage and by dissolved gases leading to voids. "

What this means to us is that the old cases may start to develop leaks from places where there is no crack or visible hole.

Clear epoxy coatings can alleviate the leakage but you have to have the case spotlessly clean before applying it.

As these cars get older, this is just going to get worse. Casting porosity is the main reason old cars leak oil no matter what you do. Most of the time it doesn't affect the function of the part.

Late 1960s GM turbo 350 and turbo 400 transmission cases had a porosity issue that was due to some casting process defects. A lot of them were replaced under a recall, but there are still some floating around. I found out about it with my first car after chasing a transmission leak for months.

Hope that helps.

Posted by: engine247 Jun 27 2023, 03:32 PM

@http://www.914world.com/bbs2/index.php?showuser=4467 I hear what you are saying so I've double checked again. I can wipe it all down and actually watch the next drop form. It's like digging a hole in the sand and watching water fill it in. The exact spot has a bit of a different texture if I run my finger over it. As for the ring area you highlighted can the case just be that porous and is saturated with gear oil?

I'll give the jb weld a shot but not sure how well it will work as the drip re-forms so fast that I doubt I can get it clean and dry long enough for the jb to set up.

Posted by: Robarabian Jun 27 2023, 04:37 PM

I think if you want to seal it with JB and it is forming that fast...

Pull the trans out (you can do it with engine still in car.
Drain it.
Turn it upside down and let anything inside drip away from that surface.
Superclean it in the method of your choice.
Texture it with something abrasive so the JB will stick and go to town.

Short of that, you are wasting your time.

Alternative: Empty trans and jack the car up so anything in that area would drip away from it for a day or two. Superclean, texture, and JB.

That might work.

Let us know how you do it and if it works. It is always interesting to learn from someone else's woes. We all have them.

Robert

QUOTE(engine247 @ Jun 27 2023, 02:32 PM)

Posted by: rjames Jun 27 2023, 05:07 PM

QUOTE(engine247 @ Jun 27 2023, 02:32 PM)

Posted by: wndsrfr Jun 27 2023, 08:48 PM

QUOTE(engine247 @ Jun 27 2023, 01:32 PM)

Posted by: engine247 Aug 30 2023, 09:43 PM

Just to follow up on this issue. I did drain the gear oil clean things up and applied jb weld. Turns out there were two leaks and I missed one. So drained things again cleaned it up again and applied jb weld again. So far so good.

Once that stopped leaking I did find that the o-ring and/or seal on the shifter console was leaking so I got to drain the gear oil again and replace the o-ring and seal. While I was there I replaced all the shifter bushing so in the end fewer leaks and better shifting. bonus.

Posted by: 930cabman Aug 31 2023, 04:57 AM

QUOTE(engine247 @ Aug 30 2023, 09:43 PM)

Posted by: mepstein Aug 31 2023, 05:00 AM

Porsche had a porosity issue on their mag engine cases. JB weld was actually the factory suggested fix.