Slow transmission leak - ZF 15MIV - Anybody used transmission leak sto

Soho

Member
419
7
Bermuda..
My ZF 15MIV tranny has a small leak - drops of fluid over a week or so @ the mooring. It was taken apart for inspection about a year ago and of course the leak started then. It is not a trivial issue to remove it for remediation on a work bench, and the leak is not so annoying as to warrant a lot of effort. I was able to tighten up the bolts holding the 2 halves of the unit together earlier this week and will go back out to see if that has helped, it had almost looked like some fluid was coming out of there, but darn hard to be sure. I was wondering if anybody has used these transmission leak stopper fluid you can buy, seems they moisturize seals and cause them to swell slightly which helps.

Thanks,

 
D

Dabnis

Guest
My ZF 15MIV tranny has a small leak - drops of fluid over a week or so @ the mooring. It was taken apart for inspection about a year ago and of course the leak started then. It is not a trivial issue to remove it for remediation on a work bench, and the leak is not so annoying as to warrant a lot of effort. I was able to tighten up the bolts holding the 2 halves of the unit together earlier this week and will go back out to see if that has helped, it had almost looked like some fluid was coming out of there, but darn hard to be sure. I was wondering if anybody has used these transmission leak stopper fluid you can buy, seems they moisturize seals and cause them to swell slightly which helps.

Thanks,
Many years ago I tried some, it didn't work. I have no idea if it is harmful to the transmission or not. Maybe

an expert can jump in? It may depend on whether the leak is coming from a seal or a surface mating source,

such as a gasket.

 

SloopJonB

Super Anarchist
68,624
12,314
Great Wet North
Those seal swellers can work a bit, for a while but they are a long way from magic cures.

More the kind of thing to use when you're selling the boat.

 

Soho

Member
419
7
Bermuda..
Probably nothing to lose by trying one. I cannot tell if it is coming from the mating surfaces housing or the other seals. Plan B is to attache a "diaper" made of those white oil absorbing cloths on the tranny to stop the leak from dripping into my pristine engine bilge. As mentioned, I tightened the bolts on the casing earlier in the week and I can see if that helped. It is only a drop at a time so it is not the biggest issue I have.... just annoying.

Thanks for the input.

 
D

Dabnis

Guest
Probably nothing to lose by trying one. I cannot tell if it is coming from the mating surfaces housing or the other seals. Plan B is to attache a "diaper" made of those white oil absorbing cloths on the tranny to stop the leak from dripping into my pristine engine bilge. As mentioned, I tightened the bolts on the casing earlier in the week and I can see if that helped. It is only a drop at a time so it is not the biggest issue I have.... just annoying.

Thanks for the input.
Yep, a drip is not too bad. We had a 3-71 Detroit diesel with a Twin Disc transmission that used to leave

a puddle after a long hard run. Just used to wipe it up after each run. Told the eventual buyer about it, I think

he said "They all do that, no problem"

 

Dex Sawash

Demi Anarchrist
2,570
796
NC USA
It is the sort of thing you try on your 1987 Nissan Sentra when $5 is all you have to spend on a repair and ignoring the problem isnt an option.

 

Soho

Member
419
7
Bermuda..
Update - the tightening of the bolts seemed to have stopped said like, perhaps not surprisingly. Need to run the boat and see what happens then.

Thanks for the input.

 

Dex Sawash

Demi Anarchrist
2,570
796
NC USA
Update - the tightening of the bolts seemed to have stopped said like, perhaps not surprisingly. Need to run the boat and see what happens then.

Thanks for the input.
Just to clarify my view on the stop-leak snake oil products, they chemically attack the seals in a way that may or may not be beneficial. They use "soothing emollients" language on the bottle like shampoo but it is a chemical attack on all the soft components.

The snake oil gets to work on all the parts, not just the one that has an annoying symptom. You may cure an external leak and cause an internal leak that causes functional symptoms

If your $100 car is leaking so much fluid that you are going broke refilling it, or the trans is slipping, pour the shit in. If it goes tits up, pull the plates off the car and walk away.

I am an auto mechanic and see all sorts of major headaches caused by the bottles of shite from autozone. I don't ever get to see the success stories though so my view is tainted.

 

beezer

Member
369
16
Annapolis
I had this transmission, or one near identical. If I remember correctly, I believe there is no firm gasket seal around the gear case mating surfaces, and it is instead sealed with permatex liquid gasket maker before the parts are reassembled. So since it was rebuilt not too long ago I doubt the "snake oil" sealer would do anything at all since you are not dealing with a dry brittle gasket that is able to swell up when the goop hits it.

If it was reassembled without a new lip seal on the output shaft, well that is another issue. The snake oil might work then, but I really doubt it since you are dealing with moving parts on a worn out seal. If it turns out you are still leaking they are not at all hard to crack open to reseal. Things get tricky when you pull it all apart to replace the clutch plates etc. Even then not too bad.

However, these hurth transmissions are garbage. So if you rebuilt because it started slipping, just wait, cause it is going to start slipping again before you know it. Give it a year if you are lucky. All that said, I would just put a drip pad under it and check the levels occasionally. Its sailing season. Crack it open now and you risk losing out on those precious weekends.

 

Soho

Member
419
7
Bermuda..
Thanks Beezer, I think you are right on the permatex front from what I can see. I actually am optimistic that the the tightening of the bolts helped as I was able to get a bit of movement on them, shame on me for not thinking of that sooner. If the leak does persist, even at a lower level, I am just going to make up some sort of diaper from drip cloth to put on it. As to the transmission itself, it has performed just fine, but I really do little motoring, our start line is about a 1/2 mile from the mooring. in almost 8 years I just have 580 hours on the engine. It is nice to have a boat and just spend about 150$ a year on fuel....

 

Soho

Member
419
7
Bermuda..
Well, when running still have the leak, coming from the seal around the shaft I think, so likely will stay until such time as I can get it out and redone. Going to fit a small drip diaper sort of thing for it. Might try the Snake Oil Sealer as little to lose.

Thanks for the input.

 

beezer

Member
369
16
Annapolis
bummer. Oil pads are cheap. Just remember to top the thing off occasionally. They do not take much fluid, and I know of two people who have inadvertently run these suckers until dry. Its always something!

 

Soho

Member
419
7
Bermuda..
Thanks for the reminder, but I do check the level just to make sure I am topped up. It is easy to do. I did notice over the weekend that the drain plug might also need a little tightening... I missed that when I did the main bolts holding it together. Regardless, the leak is not too bad given I am rarely motoring more than 30-60 minutes. I will tighten the drain plug, and check again and then make my little diaper thing.

 




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