[savethemanual]

The seals may or may not be damaged too badly to work. I would change and refill the differential and then completely clean the area around all seals and watch it carefully for a few weeks under different operating conditions being sure to keep an eye on the fluid level. Note that seals can leak under different conditions and bad seals often leak when cold while the leak due to a clogged vent will occur when hot. Seal damage also occurs from the axle assembly pulling air (and road grime) past the seals when it cools with a clogged vent tube. If the original differential lube is still in there it will have a fair amount of metal content from original break in operation wear and if air/debris is being pulled back in past the seals then that will also wear them further.

The ATS axle seals are similar to what happens when an engine PCV system gets clogged causing blowby in the crankcase to find a new escape which is through the seals and it will carry oil with it. In many cases, the problem is resolved if the issue is caught early before seal damage is extreme but sometimes a seal is compromised right away. Replacing the vent, filling, and cleaning the axle is cheap and easy compared to $1,200 so I would do that first. Fluid for the diff is also cheap and the ATS doesn't hold much so I would drain and replace it during this process.

There is a fair amount of labor involved in changing seals but $1,200 is probably significantly more than an independent shop would charge so shop around if you are going through with seal replacement.

Rodger

Thanks Rodger I appreciate the feedback!

 

[rsingl]

You are welcome! Good luck with your ATS.

Rodger

 

[Sydtron]

They may not all be 16mm. I tried that one on mine and it was too big for my vent. I believe it was 9/16th. Mine's a 2013 with the LSD.

Sergio, what was the part number for your LSD diff vent? 23156298 is not it (although if someone wants that part no., I got one!) and I'm having trouble finding the proper vent.

edit - I think it is 22929622. Here's hoping that's also what you got!

 

[Sergio526]

Sergio, what was the part number for your LSD diff vent? 23156298 is not it (although if someone wants that part no., I got one!) and I'm having trouble finding the proper vent.

edit - I think it is 22929622. Here's hoping that's also what you got!

I never replaced mine, only cleaned the one that came with my last diff. Like you said, when I look up the ATS on one of the part sites, I get two different vent numbers, 23156298 and 22929622, so I'd bet that's the one. Based on the description, the second one might be smaller than the first, which would fit with the different wrench sizes I'm seeing on here (16mm being bigger than my 9/16th vent).

 

[SaveTheManuals]

When I look up 22929622, it is listed as superseded by 23156298 in September of 2014. So it would seem 23156298 would be the correct part, no?

22929622

Rear Axle Housing Vent 22929622 | Auto Parts Express

OEM 22929622 - Rear Axle Housing Vent

www.gmpartsonline.net

23156298

2020-2022 Cadillac CT4 Rear Axle Housing Vent 23156298 | Auto Parts Express

OEM 2020-2022 Cadillac CT4 Part # 23156298 - Rear Axle Housing Vent

www.gmpartsonline.net

23156298 is not it (although if someone wants that part no., I got one!) and I'm having trouble finding the proper vent.

edit - I think it is 22929622. Here's hoping that's also what you got!

How do you know it is not 23156298? Are you basing this statement off the different wrench size needed to remove it?

...when I look up the ATS on one of the part sites, I get two different vent numbers, 23156298 and 22929622...

Every parts site diagram shows the vent, but does not identify it with a number to reference and find in the individual parts list below. The only way I can bring it up is to search for these two part numbers. What site are you using that lets you find it in an actual diagram?

 

[Sergio526]

Every parts site diagram shows the vent, but does not identify it with a number to reference and find in the individual parts list below. The only way I can bring it up is to search for these two part numbers. What site are you using that lets you find it in an actual diagram?

For this particular search, GMPartsGiant is the one that actually had the two different vents posted:

2013 Cadillac ATS Parts - GMPartsGiant.com

Shop OEM 2013 Cadillac ATS Parts at wholesale prices. You will find everything you need in this complete online parts catalog for 2013 Cadillac ATS.

www.gmpartsgiant.com

 

[SaveTheManuals]

For this particular search, GMPartsGiant is the one that actually had the two different vents posted:

Thank you. When I searched my make/ model/year, both part numbers came up BUT it said add vehicle specifics to narrow results. So I did that, adding engine/trans/trim, etc, and it still listed both part numbers. Argh.

When I look up 22929622 on other sites, it is listed as superseded by 23156298 in September of 2014. So it would seem 23156298 would be the correct new/revised part to use...hmmm....

 

[savethemanual]

I ordered mine from GM and this is what the bag looks like, I still haven't swapped the vent to see if this will fit. But I'm thinking of selling the car. Albeit the car is fun and love the handling, I don't want to deal with hassles from a daily driver.

 

[SaveTheManuals]

My factory vent (left) and brand new #23156298 (right) I bought off RockAuto. The only difference is the cap doesn't have as much room under it on the new vent, which has me thinking any pressure is escaping easier with the factory vent (or maybe this is the spring losing tension over time?). I cleaned the factory one and blew through both it and the new one, and maybe it was placebo but I feel like the factory one did not take as much effort to release the pressure. This is the 2nd time I've taken the factory vent off, considered installing the new one, and just putting the old one back on again haha.

These are both 5/8" hex for my 2014 RWD Performance 2.0T 6spd manual w/build date of 4/2014.

Again as I got the vent nearly off the diff, there was a faint pssst sound...the case either letting air out, or perhaps sucking air in?

20201025_162618 by C B, on Flickr

.

Whoa...we have the same username, like exactly. haha. But great message!

 

[rsingl]

Save,

I don't like that it is equalizing pressure when you remove it, equalization should occur with it in place and relieving vacuum via the axle seals is arguably worse than venting pressure through them because you are pulling outside debris into the seals which leads to seal damage and leakage. The axle should remain at atmospheric with the seals maintaining integrity only against changes in metal dimension due to heat changes and resisting splash but not actual changes, neither positive nor negative with respect to outside atmosphere, in hydraulic/air pressure.

I think the long term solution would be the second style vent with a barb for a hose.

And I love Home Depot's second bullet point. It is great that these magic axle vents direct torque to the drive wheels, apparently regular axle vents allow some of the engine torque to leak away to the non-driven wheels Or maybe if you use a lesser vent you automatically convert your RWD to an AWD system... Maybe those bullet points refer specifically to the ATS system where a failed vent leads to a destroyed diff and then the torque is no longer transferred to the driven wheels.


Too bad they don't have another magic vent to turn an open diff into a positraction unit

Rodger

 

[rand49er]

Save,

I don't like that it is equalizing pressure when you remove it, equalization should occur with it in place and relieving vacuum via the axle seals is arguably worse than venting pressure through them because you are pulling outside debris into the seals which leads to seal damage and leakage. The axle should remain at atmospheric with the seals maintaining integrity only against changes in metal dimension due to heat changes and resisting splash but not actual changes, neither positive nor negative with respect to outside atmosphere, in hydraulic/air pressure.

I think the long term solution would be the second style vent with a barb for a hose.

And I love Home Depot's second bullet point. It is great that these magic axle vents direct torque to the drive wheels, apparently regular axle vents allow some of the engine torque to leak away to the non-driven wheels Or maybe if you use a lesser vent you automatically convert your RWD to an AWD system... Maybe those bullet points refer specifically to the ATS system where a failed vent leads to a destroyed diff and then the torque is no longer transferred to the driven wheels.


Too bad they don't have another magic vent to turn an open diff into a positraction unit

Rodger


View attachment 589393 View attachment 589394

"Directs torque towards drive wheels for smooth cornering." What a load of manure! (I'm assuming this comment is referring to the vent itself.)

 

[ZeGerman]

[...]
Again as I got the vent nearly off the diff, there was a faint pssst sound...the case either letting air out, or perhaps sucking air in?
[...]

A thought on this ... when you drive the car, the diff heats up. The fluid and the air inside as well, so they expand and inside is overpressure. The overpressure is regulated by the vent plug.
But when you park the car, the diff cools down, the fluid and the air inside "shrink". As the rubber plate of the vent seals the opening, a pressure equalization the other way round is not possible.

In combination with the "blocked" vent it creates a vaccuum or negative pressure inside the housing.

So soaked in air due to pressure equalization could cause the faint pssst sound when losing the thread.


Well, I am not a mechanic, but correct me, if I am wrong

 

[Sergio526]

A thought on this ... when you drive the car, the diff heats up. The fluid and the air inside as well, so they expand and inside is overpressure. The overpressure is regulated by the vent plug.
But when you park the car, the diff cools down, the fluid and the air inside "shrink". As the rubber plate of the vent seals the opening, a pressure equalization the other way round is not possible.

In combination with the "blocked" vent it creates a vaccuum or negative pressure inside the housing.

So soaked in air due to pressure equalization could cause the faint pssst sound when losing the thread.


Well, I am not a mechanic, but correct me, if I am wrong

I agree. I also noticed that the (cold) diff hissed when I removed the vent. Since the membrane inside moved freely when I pushed on it with a toothpick (so, from where air would push out from inside the diff), I figured the hiss was from air getting sucked in passed the few threads left.

 

[Sydtron]

How do you know it is not 23156298? Are you basing this statement off the different wrench size needed to remove it?

Pulled the vent out and it was a totally different size than the one I had received. I should receive the correct vent soon, I'll update how that goes when I get it.

 

[savethemanual]

My factory vent (left) and brand new #23156298 (right) I bought off RockAuto. The only difference is the cap doesn't have as much room under it on the new vent, which has me thinking any pressure is escaping easier with the factory vent (or maybe this is the spring losing tension over time?). I cleaned the factory one and blew through both it and the new one, and maybe it was placebo but I feel like the factory one did not take as much effort to release the pressure. This is the 2nd time I've taken the factory vent off, considered installing the new one, and just putting the old one back on again haha.

These are both 5/8" hex for my 2014 RWD Performance 2.0T 6spd manual w/build date of 4/2014.

Again as I got the vent nearly off the diff, there was a faint pssst sound...the case either letting air out, or perhaps sucking air in?

20201025_162618 by C B, on Flickr



Whoa...we have the same username, like exactly. haha. But great message!

Haha, awesome! By the way, was your differential leaking fluid before you swapped the vent?

 

[DavidATS]

Is there an instance where someone had a leaking seal, replaced the vent and it stopped? I am wondering if the vent port has been proven to be the problem or it is a good theory.

 

[rand49er]

Is there an instance where someone had a leaking seal, replaced the vent and it stopped? I am wondering if the vent port has been proven to be the problem or it is a good theory.

In my last rear axle seal replacement (Aug '20), I stressed to the service writer to have the mechanic look at the vent. They did, but they did not replace it. Said it seemed to be working fine.

DavidATS, so what you're suggesting is that someone who has leaking seals just replace the vent itself and not touch the seals and see if that halts the leaking. Obviously, who ever did this would have to wipe the telltale fluid off the diff after the vent was replaced to see if the leakage starts up again ... or not. However, if the seals once start leaking, are they permanently damaged and will leak regardless at that point? I don't know for certain.

 

[DavidATS]

In my last rear axle seal replacement (Aug '20), I stressed to the service writer to have the mechanic look at the vent. They did, but they did not replace it. Said it seemed to be working fine.

DavidATS, so what you're suggesting is that someone who has leaking seals just replace the vent itself and not touch the seals and see if that halts the leaking. Obviously, who ever did this would have to wipe the telltale fluid off the diff after the vent was replaced to see if the leakage starts up again ... or not. However, if the seals once start leaking, are they permanently damaged and will leak regardless at that point? I don't know for certain.

I wasn't suggesting anything just that it seems like the vent has been decided to be a likely cause but I didn't know if anything has been proven or how this theory came to be. Best I can tell it is a theory with no proof but possibly I missed the proof part. As you said it's possible that once a seal leaks nothing you do matters, it's also possible the seal is a bad design, installation is difficult or done wrong, or that there are quality control problems with the seal itself (maybe more options?).

 

[rand49er]

I wasn't suggesting anything just that it seems like the vent has been decided to be a likely cause but I didn't know if anything has been proven or how this theory came to be. Best I can tell it is a theory with no proof but possibly I missed the proof part. As you said it's possible that once a seal leaks nothing you do matters, it's also possible the seal is a bad design, installation is difficult or done wrong, or that there are quality control problems with the seal itself (maybe more options?).

Oh, it’s just a theory as far as I know. If anyone has a different theory, let’s hear it. Then, let’s test it and come to a resolution as to what’s going on. Finally, we can sell it to GM and make a few bucks ... for the forum, of course.

 

[DadillacATS]

so to clean the vent out just remove it and blow out with compressed air and reinstall?