Transmission Leak at the shaft

Hi All,

Recently, the starboard transmission (BorgWarn) started to leak right at the flange where the shaft comes out. It was enough ATF loss that I was down to the 1/2 mark on the dip stick after six hours of motoring.

I guess it's a seal. Thoughts?

Chris

Greetings,
Mr. CL. Sounds like a seal. I had had a leaking seal for a couple of years that I finally changed. NOT a big job. Two things I can suggest: 1) Make a piece of angle iron with two drilled holes that you can bolt onto your flange, using two adjacent bolt holes, for removal and tightening that big nut you'll find holding the flange half onto the transmission. 2) Beg, borrow or steal a LARGE socket and breaker bar for removal/replacement (and proper torque) of aforementioned nut.
Partially drain fluid out of the transmission so as not to slop fluid all over your bilges (have lots of diapers handy). Get a tube of RTV silicone, yes, silicone (I don't believe I just said that) for sealing the nut upon re-assembly.
Took me about 2-3 hrs of easy work. Next time it should go a lot faster.

Rear seal.

RT, I'm gobsmacked! You actually advocated the use of the dreaded s...s...s... I can't say it!

Pack the entire coupler cavity with RTV, put on new nut and torque to 200 pounds or as close as you can get then spread the rest of the RTV over the nut. It is a one-time nut and cannot be reused.

meridian said:

Pack the entire coupler cavity with RTV, put on new nut and torque to 200 pounds or as close as you can get then spread the rest of the RTV over the nut. It is a one-time nut and cannot be reused.

Click to expand...

Or you could just replace the seal.

Sometimes nut loosens, and it leaks through the splines and threads. If you can pull back shaft easily, check for a loose nut.

Might want to check the shaft for alignment, after repairing the leak.

The coupling comes off to replace the seal.

meridian said:

The coupling comes off to replace the seal.

Click to expand...

The shaft coupling and shaft have to be moved back out of the way either way.

Unless you are talking about the flange on the end of the transmission that the coupling attaches to.

Gentleman,

Thanks all for the feed back.

Should I replace both while I'm doing the repair or just wait and see if ever needed?

I`d wait and see. Look for reasons one seal failed, old age, misalignment, in my case a bent shaft. You do need to realign.

Greetings,
Mr. CL. Buy 2 seals, do the leaking one now. If and when the time comes to do the other, you will have the tools (hopefully), the part and the know-how. If you never have to do the other side, what have you lost? $10?

Location of leak



Capt Bill,

That's where it is leaking from, at the flange that is bolted to the shaft. See photo, leaking at the blue tape.

Sounds like the fluid is migrating along a gap between the shaft and coupler. Perhaps through the key way.

But you still think it's the rear seal?

ChrisL said:

But you still think it's the rear seal?

Click to expand...

I would say that it is.
Although it is possible that the oil is following the shaft splines and coming out at the nut. But once you are there the seal is easy to change.

If you would like a copy of the BW repair manual in pdf send me your e address.

jleonard@globalsteering.com

The shop manual says the coupling nut must be replaced when the seal is replaced. Torque is 220 to 260 ftlb. If ordering a new seal will also need a new coupling nut.

ChrisL said:

But you still think it's the rear seal?

Click to expand...

Yes. Unless you can see/find another source for the oil you see.

That is one reason I like running ATF in those transmissions. You can tell right away by the color of that is the source of a leak.

BW manual.

jleonard said:

I would say that it is.
Although it is possible that the oil is following the shaft splines and coming out at the nut. But once you are there the seal is easy to change.

If you would like a copy of the BW repair manual in pdf send me your e address.

jleonard@globalsteering.com

Click to expand...

Great! I will send an email this morning.

Thanks,

An early sign of failure is a very fine line of oil appearing on fixed surrounding areas,spun off the spinning drive

Transmission Leak

Hey Bruce,

At first, that's exactly how I noticed the leak. Oil that had been spun off the shaft or flange had sprayed around the bilge, hoses and stringer.

Thanks everyone for your comments and feedback. As always, much appreciated.

If you plan to use silicone [] or any sealant the surfaces and threads must be hospital clean.

Perfect timing on this thread... last week the neighbor invited me for a boat ride. Prior to leaving he raised the hatch to check the fluid levels and look in the bilge. There was a sheen of oil down there. Checking confirmed it was transmission fluid.

Pink equals tranny fluid.

In any event he looked at the situation, spotting some wires back by the shaft. When I volunteered a fresh set of eyes he agreed.

This is what I saw:



I recognized this having seen it before. On that boat the shaft was darn near removed from the boat by the wires.

So, we removed the wires and then refilled the tranny. The next day, this:


We ran the engine. She shifted into and out of gear a-okay. There was no transmission fluid on the diaper after running. Still there was that drip and the owner wanted to make sure all was well re the wires/drip, etc.

Well, it's been a week and all the ATF has drained out. We've got a leak. My expertise ended at removing the wires. The drip (I can feel it) appears to be coming from where the shaft enters the transmission. The white transmission has fresh AFT on it.

Here's a better picture of the mess before wire removal:


So, what's next? Remove the coupler? Then? And thanks!

Looks like a Hurth/ZF 630 or 800. I don't know if coupling comes off the end of the shaft allowing access to the seal. I'll go see if I can find out.

Edit: Looks like a central bolt holds the flange on, so pull out the bolt and use a puller to take off flange. The seal can be replaced in situ. Bolt is 74ft lb.