There's really not much in there that can actually develope pressure.
Tubulence to be sure, but nothing remotely like base pressure as found in an engine.
They're more for ventilating moisture content as I understand it.

The vents come off, and IIRC, are not much more than screens on shaped housings.
The gearbox subsection of the forum is almost assured to have a description and likely even schematics and photos of the vents.

Just for pure amusement purposes, how good is the condition of your TX mount?
If its weak or shot, the TX tips back, and with that more oil pools in the section of the box that contains the vents amplifying the odds that the vents will end up passing some oil instead of just steam or air.

 

Dredged this up which may be of use.
Vents are item #14.
Do note that they also represent the pivot mounts for the shifter mechanism item #12, so if you're gonna pull things down, it might be worth your while to take one side apart ado whatever and get it reassembled before tackling the other side.
Otherwise the mechanism 'may' displace in the tower and you'd then be in for way more fun that you initally anticipated.

 

I've only had the car a couple months, and little by little I've been checking things out. When I was under the car looking for the leak, and wiping up the oil and grime, I noticed the 3 mounts under the gearbox/shifter and they certainly aren't new, and are on my list of things to get to including almost every other rubber bushing under the car. Do you really think this could be it? Thanks.

 

Thanks for the diagram. I had already dug that up myself and never noticed those assemblies locked the shifter pin in place. I also never noticed what looks to be a double gasket behind them. I'll have to check for the gaskets, but why leaking now and not all along. Mind you while trying re-install the shifter knob, even with a little grease, I had to pound on the knob to get it on the shaft. I wonder if it was enough to crack the seal on the gaskets???
Thanks.

 

These transes are known to spit out a fair amount of oil; the gears themselves act as an oil pump. The boots all need to be in place, not torn, and well clamps to keep the oil from draining down the side of the tower. The innermost boot that clamps right at the top, just below the edge, is supposed to keep the oil in the "sliders" area draining back into the trans. There were period racing mods to encourage this, which I think did not get worked back into the stock cars.
If your vents are clogged, the trans will spit more oil out. And if it's overfull, it will too.
Andrew

 

Mike,
I had a similar problem with my giulietta but the oil leak was coming from the shifter tower and not the vents. See this thread for the problem and solution.

http://www.alfabb.com/bb/forums/giulietta-giulia-1954-65/180065-transmission-oil-leaks.html

 

I had a similar problem. Turned out to be the inside boot clamp came off. I put it back on and wrapped a wire tie around the clasp as a bit of insurance.

 

Shims

Related to the subject, I would like to know people's opinion on using a minimal amount of RTV or such on the shims and the vents, 14 above?

I know that the factory didnt use any when they assembled, but it just doesnt seem right to me after all of these years.

When I pulled mine for a similiar leak, mine were a tiny bit rusted. I wiped them as clean as I could but couldn't get the rust off.

Like I said, interested to hear others.

Vin

 

I've just gone back inside the shifter boot (but I haven't removed the console), so I have everything lifted up out of the way, and I'm looking in from the side. I saw the drain hole at the cabin side of the shifter tower and it didn't look gummed over. I grabbed a 90 degree dental pick and went poking around it, and I can't stick anything deep into it. In the picture, it looks like the pick should be able to go in quite a bit. If so, what could be obstructing it. Are any of the sliding plates under the shifter able to turn and cover the drain, or when I had those parts out and wiped them down before re-installing them, could I have installed them out of rotational orientation. I know I have all the parts in there and in order. I know the picture shown was a much older model car, is the drain different in series 3/4 models.

Thanks.

 

In the picture, it looks like the pick should be able to go in quite a bit.

I can't speak for the later spider transmissions, but the drain hole on the 101 transmissions goes clear through straight down. You might want to try a small finishing nail or straight pick and press straight down to break through the gunk. Are you able to scrape out gunk with the pick? If so, keep scraping and digging, you will break through eventually. Can you take pictures of what you see?

 

The tower on my series 3 and friends series 4 are a little different as there are 3 drains equally spaced out around the diameter. I checked them and they all are about 1/4" deep and then hit a surface which I guess is the machined seat in the tower for the steel ring to seat. Since I wasn't working from above with the console removed to be able to see better, I think the ring is then undercut in those areas to allow the fluid to drain back into the gearbox.

While its obvious by the pics that your drain was plugged and clearing it helped, I beleive mine are fine and it was still a worthwhile shot. I'm also convinced mine are clear because if they were plugged, I probably would have had fluid pouring out from the boot as soon as I loosened it off the tower.

I'm going to button it all back up again and see what happens and will report back.

 

Great thread, I suspect 2 out of 3 vintage alfas have this issue! I am in the same boat as the gear lever seal is not present. I see from the parts book that there is another metal "washer" (it is called a "gland" in the parts manual - part 105.08.13.624.00 and item 4 in the diagram Tifosi posted), and am a bit curious about the assembly order of this "gland". The rubber seal (item 5) could stretch over the shoulder on the gear lever, but is this gland supposed to sit above the shoulder on the gear lever and hold the rubber seal down? I can't quite see the function of this part yet... If it goes underneath the shoulder, then wouldn't one have to disassemble quite a bit of the back of the tranny to get this on? If someone has a photo of the assembled piece that would be much appreciated.
thanks

 

I see from the parts book that there is another metal "washer" (it is called a "gland" in the parts manual - part 105.08.13.624.00 and item 4 in the diagram Tifosi posted), and am a bit curious about the assembly order of this "gland". The rubber seal (item 5) could stretch over the shoulder on the gear lever, but is this gland supposed to sit above the shoulder on the gear lever and hold the rubber seal down? If someone has a photo of the assembled piece that would be much appreciated.
thanks

euro1750,

Yes, there is supposed to be a rubber seal and a metal washer on top of the seal. I would guess it is to keep oil from splashing out that hole.

I replaced mine while I was in there as it was well worn.

Here are some pictures.

Rubber seal. Old on the left new on the right

Metal washer seen just to the right of the shifter

Assembled on the transmission shifter tower

Good luck,

Vin

 

Thanks Vin,
I was thinking the seal was held in place by the boss on the shift lever (that sticks out of the tranny), but it looks like it fits around this lever, and then is held in place by the washer, which is pushed down from the installation of the gearshifter itself. Makes sense!
I guess a good smearing of grease would be a good idea on the spherical plates when reassembling too.
thanks again!

 

I guess a good smearing of grease would be a good idea on the spherical plates when reassembling too

They'll self lube via splashed oil.

If you're thinking of grease to help seal, it might for a very short period of time, but before long it'll end up in wads on the inside of the rubber boot making oil drainback even more difficult so you'll get pooling which in turn will make it more probable to leak, which you're trying to prevent to begin with.

 

I'm still leaking gearbox fluid from up in that area. I've had the boot off a second time and checked the drains and they were ok. I re-installed the boot and its good and snug. I've driven the car up and down ramps in the garage a few times, and I'm already seeing gearbox fluid under the vent assemblies.

Couple things...

1. Has anybody had leaks thru the vent assemblies - past the shims/seals. Could it hurt to try a lick of sealent? Any dangers of doing this providing it do one side at a time (remove - clean- seal - re-install.)

2. I still have all the access panels off and the steel cover sitting loosely in there. When the car is running, its it normal to hear a hissing type sound coming from the gearbox (almost sounds like the sound of being in the house and hearing the water running through an outside tap - or the sound of a kettle starting to boil). It increases with rpm and goes away when in neutral or when pressing in the clutch. Just wondering if this is normal or could be a symptom of my leak.

Thanks.

 

1. Has anybody had leaks thru the vent assemblies - past the shims/seals. Could it hurt to try a lick of sealent? Any dangers of doing this providing it do one side at a time (remove - clean- seal - re-install.)

Mike I was thinking the same thing.

Not like we see a lot pictures in that area, but I found one of Msiert's and there is definitely something being used.

If you do use some sealant, it will have to go on every surface that comes into contact with each other. Meaning, sealant has to go on each side of every shim.

Good luck,

Vin

 

Thanks Vince, I will PM Misert and ask if he did it as a precaution or as a result of a leak.

 

Update:

I removed the vent assemblies and used sealant on the re-assembly... and there are no longer drips hanging from the bottom of them.

I re-seated the shifter boot.

I was still getting a leak in that area, so I put dye in the gearbox oil (suggestion of Vintre) and checked with special flashlight. Both the bottom of the boot and bottom of the gearbox output shaft seal were wet and the surrounding area. I finally thought to seperate the seal from the boot, but attaching a towel to the tower, and see which side of the towel was wet... Turns out its the seal and the spinning shaft would flick oil all around including up to the boot making it look like the boot was still leaking.

Today brought the car to a local Alfa expert who also confirmed its the seal. He also noticed the differential front yoke seal was leaking. Both gearbox and differential were dry 3.5 months ago when I bought the car and before I switched to Redline.

If you were me, would you switch back to Shell Spirax hoping it'll stop leaking or change the seals. If change the seals, any direction on how to change the seals would be great.

Thanks.

 

I would replace the seals and then use whichever oil seems to work best or that you prefer. The 75W-90NS is a good option in the gearbox. I am not aware of any specific benefit to using a special gear oil in the differential though. As far as I know, any good quality 80W-90 GL5 rated gear oil should work fine in that application.

Thanks for this thread. I had not considered the vents or the drains as potential sources for or contributors to gearbox leaks.

P.S. Search for "pinion seal" and "transmission seal" for R/R info.

 

Gotta love the BB. I'm in the process of changing the rubber shifter boots and cleaning out the gearbox vents, and just happened across this thread and post #3. So I removed and cleaned the item 14s in the diagram one at a time rather than both at once. The shifter handle is still attached, so that may have prevented disaster had I removed them both, but better safe that sorry.

But one other possible trap for the unwary: There is a spacer/washer on each of the pivot arms of item 12 (one is shown in the diagram) -- a thick one on the right and a thin one on the left in the car I'm working on. These each came out with the associated item 14, oil surface tension holding the two parts together. But I could easily imagine a spacer attempting a leap to freedom, and ending up in the bottom of the 'box.