Differential and gearbox breathers

JNijst · Post by **JNijst** » Sun Feb 28, 2010 1:23 pm

I keep reading about differential and gearbox breathers.
Do we have these on the Pinz ? I did read about it on the German Forum, but little on this 4x4 forum.
Neither did I read anything in the original German Service-book.

IF there are breathers, are they just short stub-valves ? or could you attach a small hose to ensure they stay above any water-intake ?

Jules

Jimm391730 · Post by **Jimm391730** » Sun Feb 28, 2010 11:45 pm

I believe the breathers are optional, some trucks have them, some don't. I guess it depended on how bored or busy the Swiss were.

For example, my 712 has two breathers - on for the front diff that is on a hose that goes up to behind the aircleaner where the hose is terminated in a plastic fuel filter to keep dust and dirt out. Likewise there is a hose from the diff switch cover on the central axle that runs up to just under the body, above the rear leaf spring. But this one has no filter, so I fed it into a hole in the chassis box member so it is not so exposed to picking up dirt.

You could run the hose for any length and as high as you want.

Jim M.
712W and 710M

undysworld · Post by **undysworld** » Mon Mar 01, 2010 6:34 am

I'd been told that the cases were not vented on purpose. That way, they develop a slight pressure when driving. This is designed to prevent water from entering the cases during fording operation. At least that's the tale I heard.

I also was told that a venting kit was available as an option, although I've never actually seen such a kit.

Paul

Jimm391730 · Post by **Jimm391730** » Mon Mar 01, 2010 5:58 pm

The venting kit is a modified 4x4/diff lock switch cover with a hose fitting for venting; it is believed that the possibility exists for a sealed sytem, hot with use, cools during water immersion and sucks in water when not vented. Hence the desire to vent the system. I've seen pictures of the kits at EI or SAV, don't remember exactly where.

YMMV. I don't do much deep water trails (unlike our friends in Florida!) so I'm not worried, either way.

Jim M.

GenevaPinz · Post by **GenevaPinz** » Fri Mar 05, 2010 7:20 am

There are a few pics of the setup on this german website:

http://www.allrad-lippe-404tg.de/galerie15.html

...and the full kit is available with SAV (#7102283300).

Jan

Lorenz · Post by **Lorenz** » Fri Apr 23, 2010 12:56 am

Sorry for my bad English first.

All vehicles after 1978/79 normally do have a breather at the front diff. AND!!! the hollow shaft which comes from the diffs to the wheels do have drilled a small hole. This hole make it possible that the gearbox (portal) can breath.

On every vehicle (also the old before 1978/79) there is a access between the diffs and the 2 Gear Gearbox. So if you want this parts to be breathed it's enough to mount a breather at the front diff. If you want that your portal-gearboxes also can breath, you have to open your diffs and you have to drill the small holes in the hollow shafts. The procedure is discibed on one page at the repair manual.

Best Wishes

Lorenz

edzz · Post by **edzz** » Sat Apr 24, 2010 1:28 am

Lorenz, no "bad English” apology needed. Your English sentence structure is much better than we are used to from the factory manuals. Thanks for the great information.
ED

pinzinator · Post by **pinzinator** » Sat Apr 24, 2010 8:03 am

I have one of those breather kits for sale, still in the factory packaging. $85 takes it, send a PM if interested.

spandit · Post by **spandit** » Tue Jun 08, 2010 2:43 pm

My 710K was made in 1975 and I have a breather fitted from the front axle (haven't checked for any more). The piece that I presume is supposed to be a fuel filter is just a hollow plastic casing - I wondered if it was a valve but you can blow through it both ways

Jerbearyukon · Post by **Jerbearyukon** » Sat Jul 24, 2010 7:47 am

I was wondering about this too....everytime I try to check the diffs I get a hissing sound as I remove the nuts....I always remove the highest one first.

ONE QUESTION IS THOUGH.

I have been having trouble with the speedo LEAKING and I am constantly adding fluid to the front diff. I have changed the seal ring several times...still leaking....I talked to Scott at EI and he is going to send me a thicker ring.

Because of the pressure built up in there it must be forcing it out of the speedo....can there be TOO MUCH PRESSURE build up.

Anyone else have this problem. It scares me cause I don't want to run it dry.....diff seals I have fixed but this is an ongoing problem.

Thanks Jer bear

Scooter · Post by **Scooter** » Sat Aug 14, 2010 9:03 pm

We have gear boxes that are sealed on machines at my work. They work just like the pinz, as the temperature/pressure builds it pushes out dirt or water around the seals. The main issue is when the gear box cools, they tend to suck the water back in around the shafts. We developed a bladder system to expand with heat but not allow the water to suck back in. Kind of like a ballon that expands and contracts with temperature change. That would be cool to have on the pinz .

Scooter

Higher Ground · Post by **Higher Ground** » Sun Aug 15, 2010 12:19 am

If you hang aroun atv shops , lookat there drive train . they have a little bellos type breather , I modified some to work on my Jeep . No water will get sucked in .