Vent location advice?

[Marc]

So I guess this is the spot recommended to add a vent for a Berg 5-speed:
http://images.thesamba.com/vw/gallery/pix/180331.jpg

I'm getting some fluid spewage out of my IRS 4-speed at sustained high speeds and am assuming that more than the stock venting is needed - the nosecone is inaccessible in place because of the cable-shift bracket (and it's rather involved to remove) so I'm thinking of just putting a fitting in over the differential.

Should I put it on the clutch-lever side instead since my ring-gear is flipped for mid-engine?

[Bruce2]

Are you sure the stock vent isn't plugged with sealer? I've seen a well known trans builder do that.

If you put it on the clutch lever side, it will work better than on the other side in a rear engine configuration since the reverse idler shaft isn't on the clutch lever side.

If you don't want to take the gearbox out and apart, but still want to add a vent, you can modify the stock filler plug. Drill and tap the center for 1/8" NPT and screw a fitting in there after you put the plug back in the case.

Berg supplies a fitting with their 5 speed kit, but I don't recommend it. They give you a ¼"NPT fitting with a large ID. To me, that large ID just promotes blowing oil out. It needs to be small, like the stock one. That's why I drill and tap the case 1/9" NPT.

[Piledriver]

Logically a larger ID fitting would have a lower velocity for a given flow, so less likely to spew...?
...Just thinkin out loud.

[sideshow]

As an experiment, why not the unloaded side cover?

[Pablo2]

Vents are usually located in a tucked away spot that sees little oil splash. You'll likely spew oil from a vent in the diff area. Porsche does it on some models, but they have a special fitting with internal lip pointing away from the oil slinging ring gear.

I doubt any extra vent is needed. Something's blocking at least a portion of the stock vent path.

[Marc]

Vents are usually located in a tucked away spot that sees little oil splash. You'll likely spew oil from a vent in the diff area. Porsche does it on some models, but they have a special fitting with internal lip pointing away from the oil slinging ring gear.

I doubt any extra vent is needed. Something's blocking at least a portion of the stock vent path.

Guess I wasn't clear. Pressure's building high enough that the (new) final drive seals are leaking - it's not coming out at the vent itself. Only happens when running at 80-90 MPH for a couple of hours (as in MT & WY) ... at 60-70 in WA it doesn't leak a drop. The only sealant on the nosecone gasket is a thin film of Curil K2 - don't think that could be a problem.

I think I'll just do as Bruce suggested to see if it makes any difference. Probably run a ⅜" ventline upwards for a foot or so and then back towards the pavement. I'm planning to pull the motor out this winter to up its size, at that time I'll put in fresh FD seals and pull the nosecone to make sure there's no obstruction.

Thanks everyone.

[Bruce2]

would have a lower velocity for a given flow, .

Even with a small hole for a vent, you couldn't measure the velocity of the flow. The amount of air that has to vent is extremely small, and that small volume of air has as much time to vent as it takes to warm the interior of the gearbox.
A big vent just promotes oil leakage.

Originally, Gene Berg put the vent on the nose cone of the 5 speed, likely because that's where VW put it. But his gearbox has 5th gear in the nose cone, and that caused oil to pump out of the vent. For a while, Berg recommended adding the filler plug vent I described above to go with the original nose cone vent. This still didn't work in all cases. Eventually someone came up with the idea to put it above the diff on the starter side since the diff rotates at approximately ¼ of the rpm of the input shaft in the nose cone.
The stock location works on a stock trans because there's little in the nose cone to fling up oil. Presumably the early gearboxes with the large nuts will fling more oil than the later shafts with circlips.

Marc, do you know the year of the nose cone? The manual has pics of the insides of some nose cones showing different passages for the vent. The changes were needed to prevent oil loss. Maybe you have one of the bad design nose cones?

[Marc]

...Marc, do you know the year of the nose cone? The manual has pics of the insides of some nose cones showing different passages for the vent. The changes were needed to prevent oil loss. Maybe you have one of the bad design nose cones?

The trans core was an early `72 and IIRC I used the nosecone that came off it. Judging from the road-grime/grunge buildup it was the original one. I'll take a good look when I have it out over the winter.

[FJCamper]

A warning here.

The stock vent is more than just a vent. It help guide oil toward itself which lubes the bearings towards the nose cone of the transaxle.

This natural siphoning is the only directional control for oil in the transaxle, as the rest is all splash lubrication.

My guess on this is the stock vent must be blocked someway, since there is oil being forced past new seals.

I have seen an improvised vent made from a backup light switch. It's in the right place to do some or all of what the stock vent might do.

FJC