So, it has come to this. The breather vent in my transfer case is properly clogged, this has been pretty much verified at the Jag-specialized workshop I go to, as trying to put in new oil into the case was exceedingly difficult and had to be done at some pressure apparently.

The clogged vent prevents air from escaping the case, so when the case gets hot as they tend to do, the thermal expansion of the oil inside causes it to expel the now-excess oil through the propshaft seal. It's probably not good for the seal in the long run, so in the words of Aristotle; "gotta fix it brah"

Here's a photo of the vent & here's a bunch of good photos of the transfer case:


The main problem is that it is reportedly impossible to reach that vent without doing some major dismantling, the time estimate for which sits at a hefty 6 hours. That translates into about $800, so I'm sure you can see how I'm not entirely chuffed at the prospect of spending that kind of money on fixing a clogged $13 vent...

Any helpful ideas are greatly appreciated, and alternate solutions are also welcome!

As a sort of ghetto-fix to keep things working, I was considering fitting an expansion tank to the transfer case drain hole. If doable in some way, that would be suitable until I encounter some reason aside from the vent good enough to warrant dropping the case.

Also, if I end up dropping the case, how can I maximize the benefit of it? Swap the possibly incorrectly pre-loaded bearings or something...?

 

Mine clogged also. Or, rather, the check valve stuck. I'm not entirely sure there is a check valve, but it certainly behaved like one. As it suddenly stopped letting me fill the gear lube and was full of pressure.

To un-stick it, I hooked a vacuum pump to the transfer case fill port and sprayed non flammable cleaner up around the vent/check valve. It worked perfectly and have not had a problem since.

When filling the TC, I had to do so slowly, or the check valve will seal.

 

Good advice there Cujet,

I am sorry to hear your woes Aonsaithya so I hope this is a good fix?

Fingers crossed, I always enjoy your fascinating facts and stylish postings and I wish you all the best, the forum needs YOU!

Regards, Stu

 

Thanks for that! If I understood correctly, the idea is to create a vacuum in the TC, that would then practically attempt to suck in the cleaner through the vent? Of course, the cleaner has to have some time to work its magic before attempting the vacuuming? The only downside I can think of is that this would then also suck into the case the semi-liquified remains of whatever it is that clogged the vent in the first place, but it's probably not a big deal.

I don't know whether there is a check valve of any sort, as at least the JEPC only mentions the breather vent (C2S11224) I squared in the photo. Is that the same spot you sprayed? If so, was it difficult? From what I understand from looking at pictures and photos, the breather vent at least is right above the front-right driveshaft, and the photo below, taken under that area makes it seem a very difficult thing to accomplish. If I'm understanding correctly, the breather vent is on the opposite side (topside) of the TC in the top part of this photo.

(not my car in this photo)


Thank you for your kind words, Stu!
Stylish posts

EDIT:
cujet, I'm starting to wonder, a vacuum pump? Because the breather vent should be one-way, exit-only. Using a vacuum pump would thus just pull it in the closed position?

 

That's what I did. I did not know the unit was configured like your drawing. I simply could not get fluid into the TC. So I used the vacuum pump to try and clear it out. Along with AVL (chlorinated solvent) spray. Worked like a champ.

May have been oil/dirt/gunk. Dunno. Could barely see the thing.

 

Thanks!

Hmm, so how did you spray the vent with the solvent? Some kind of a long tube, or just aimed at the general area? I assume you let it do its magic for some time before applying the pump? What route did you take to get to the vent (as it's in such a difficult location)?

 

I was angry, confused and otherwise irritated at my Jaguar. So, I simply used my air cond vacuum pump, a wet rag to form a seal and a spray can aimed and discharged in the general direction. I really can't remember if this was the time I had the bumper and tires off for headlight repair or not. But, in any case, it was nearly impossible to see the vent.

Believe it or not, the TC has been trouble free since I did this and replaced the prop shaft TC bearings. I wish I could be more help, but simply picture an angry mechanic grasping at straws to find a "fix" and you'll get the idea!

If it worked for me, it's likely to work for you too.

 

To me it looked like it'd be completely impossible to see the vent at least from beneath the car.

I guess I understand your method better now, it'll only work however if the vent isn't completely clogged, as some air must be able to pass through for the vacuum pump to suck the sprayed stuff in through the vent?

I'll have a shot that, thanks! I'll also try blowing air in, in case that makes any difference, in an effort to get the vent moving.

UPDATE:
Haven't tried this yet, but if I end up having it done the hard proper lengthy expensive way, the workshop suggested that the oil pan gasket be pre-emptively replaced at the same time. It is a fairly good idea as it should probably be replaced in a 13-year old car at some point anyway, and $1100 now instead of $800 now plus $1000 later does admittedly make sense.

UPDATE2:
Another workshop said they have experience with this very issue, so I went there. They sprayed some sort of stuff (I wasn't present at the moment) at the vent, pressurized the case, and the vent reportedly opened with a hiss. As I feared, the oil coming through the propshaft seal (which was fixed in 2012) had broken the seal, so it had to be replaced. Now I think I can lay this issue to rest.

 

I would not think the vent would be a check valve. As it heats up and cools down the pressure in side of the case goes up and dowm.


I have seen vents that look the same that are just tubes with a loose cap on the top.


Thanks for all the info.

 

I have a similar problem. I changed the TC oil by tipping the car on its side and adding oil through the plug on the side. After that, it has had a burning oil smell and I can see the right side of the oil pan is damp, and I had oil on the CV boot on the right side and it was dripping off the serpentine belt tensioner.

I looked as best I could and it appears the oil is coming from the RH output shaft seal on the transfer case. Could it really be the vent is clogged, or oil is still seeping from the vent as the car is driven?

The black triangular piece in the photos gets wet with oil and drips onto the exhaust.