Recently I took my car in for oil change and they discovered that one of the rear axle seal has a leak. It was repaired under warranty. I read in this forum that this has many times caused by a clogged vent port. I am curious to remove the vent port to inspect and clean if necessary. Does anyone has the instruction or know the location of this port? I have the 2.0 without LSD. Thanks
ATS rear differential vent port
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ahs2m2
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Yeah, I think you'd remember something like that, so don't tinker with it until your next cleaning.
Reverse threads are uncommon in cars, at least US vehicles. Last time I can remember messing with them was the ring gear bolts on a type O diff I had under a 442. Man did I use a ton of torque trying to get the 1st one off!
Mine is a 2016
As few other posters pointed out, I could very well been disoriented when working from below with the tight space. I have edited my post to not cause any confusion to future readers
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How do i find out if i have a LSD or open? And what fluid would i need to do a flush?
If you have a manual transmission or Premium trim, you have LSD. Fluid PNs in this thread:
ATS differential fluid change and vent clean
I originally did the diff fluid sometime after I got it used w/17k on it in 2014. Fluid didn't look too bad, but it had a disturbing amount of crud stuck to the magnetic tips on the fill & drain plugs, like a thick paste. Probably break in material worn off the gears. So decided to do it again...
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Watch your RPO sticker in the trunk. When the code "G80" is listed, your car has the LSD.
2015 ATS Coupe, Premium 3.6 AWD; 2005 Mercedes SLK roadster; 2003 Suburban
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Partly true for Premium trim. No LSD for AWD -- just RWD.If you have a manual transmission or Premium trim, you have LSD. Fluid PNs in this thread:
ATS differential fluid change and vent clean
I originally did the diff fluid sometime after I got it used w/17k on it in 2014. Fluid didn't look too bad, but it had a disturbing amount of crud stuck to the magnetic tips on the fill & drain plugs, like a thick paste. Probably break in material worn off the gears. So decided to do it again...
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Tyvm guys
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So wait now im confused lol i have RWD, but im Luxury, not premium.
2016 ats 2.0 8sp a/t
^he was saying premium AWD models do not have LSD, just the RWD ones.
I removed the diff vent on my 2014 manual Performance yesterday to look at it. I used a 5/8" box wrench, it was certainly snug on there but nothing crazy to break it free. Also it was not reverse threaded, nor did I need to jack up the car to do it. This was the first time I have removed the vent myself. It may have been cleaned when I had my axle seals replaced at 44k miles, never did verify that. I may be mistaken, but I thought I might have heard a tiny "hiss" when I unscrewed the vent...if that did happen I guess that could mean the vent was somewhat clogged and pressure was slowly venting prior to me unscrewing it enough, or the vent was clogged completely and this was pressure that had built up. I have no leaks right now, diff is dry.
I looked through several threads here to try and take it apart to clean it, but ultimately I did not feel comfortable trying to pop the cap off with it being the only vent I have currently. I ordered a new OEM vent off RockAuto for $16.53. When I get the new one I will be checking the diff fluid level & topping off fluid to top of file hole if needed, and installing the new vent. For now I just turned the cap some and pressed it up and down and some grime dropped out. Seemed a pretty decent amount.
I will take the old vent apart and mess with it a little, try cutting the spring as someone else mentioned to see if/how that changes tension. I would like to go to ACE Hardware and look for a barb with the same thread pitch and pair that with a hose, then figure out how and where to route the hose up into the bodywork and then back over so the end of the hose is facing the ground. Then figure out a way to mount the hose so it stays in the shape and location I want. Does that sound right? I have heard a few people say having a hose is a better solution and a surefire way to ensure venting the diff stays clog-free. But I'm not sure if the hose should just face up or if it needs to turn 180 degrees toward the ground.
I looked through several threads here to try and take it apart to clean it, but ultimately I did not feel comfortable trying to pop the cap off with it being the only vent I have currently. I ordered a new OEM vent off RockAuto for $16.53. When I get the new one I will be checking the diff fluid level & topping off fluid to top of file hole if needed, and installing the new vent. For now I just turned the cap some and pressed it up and down and some grime dropped out. Seemed a pretty decent amount.
I will take the old vent apart and mess with it a little, try cutting the spring as someone else mentioned to see if/how that changes tension. I would like to go to ACE Hardware and look for a barb with the same thread pitch and pair that with a hose, then figure out how and where to route the hose up into the bodywork and then back over so the end of the hose is facing the ground. Then figure out a way to mount the hose so it stays in the shape and location I want. Does that sound right? I have heard a few people say having a hose is a better solution and a surefire way to ensure venting the diff stays clog-free. But I'm not sure if the hose should just face up or if it needs to turn 180 degrees toward the ground.
I also found this stamping on the diff housing just below the vent hole. '40075260', which I assume is the part number. But just below it was 'REV B'. Would this stand for Revision B, meaning my car has a differential that was revised in some way when my car was built in April 2014?
Here's my take on all of this, and my ATS still has the original differential seals that have never leaked. If pressure builds up in the differential to where oil is forced past a seal, does this necessarily damage the seal? I would think the flexible lip that contacts the rotating shaft would spring back to normal after acting as a by-pass valve. If the problem can be repaired, why would the seals need to be replaced? I could be completely wrong, so someone correct me. I know a damaged or worn seal will always leak.
In my opinion, a short rubber hose with a filter would work better as a vent, as long as it is positioned to where it could not let water in.
In my opinion, a short rubber hose with a filter would work better as a vent, as long as it is positioned to where it could not let water in.
I agree but the problem is once a seal is leaking you don't know if it is a faulty seal or pressure or if once a seal leaks if it is more likely to leak going forward. Unless something changes like removing the pressure or replacing the seal it will continue to leak so your questions are correct we just don't know. When you take it to a repair shop with a leaky seal the best option they have is replace the seal. You personally could continue to refill it or try to solve the problem with changing the vent some way but a repair shop isn't likely to have a customer that understands or wants to bother with it.
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So, you guys are saying that replacing the seals may not be necessary, and by doing so is like treating the symptoms and not the core issue, i.e. the vent. Could it be that by fixing a clogged vent the leaking will stop and all will be well again?
I'm going to look into doing what SaveTheManuals has done and maybe order a vent.
What's the P/N for the LSD vent? My diff is wet on the passenger side, again. I had axle seals done last year, but maybe just replacing the vent and making sure diff fluid is topped off will keep me from needing to do seals again.
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Twelve bucks at rockauto (excluding sales tax and shipping).
Hi, I recently took my ATS with a LSD to get diagnosed at the dealership. I noticed the differential was dirty and hence leaking somewhere. The diagnose was that the differential vent is clogged, hence the reason the differential is leaking from both sides. Quoted at $1,200 for repairs. My question is couldn't I simply clean the exterior of the differential, swap the vent and see if the differential stops leaking? or should I change the differential gaskets also? Thanks
2024 CT5 V RWD, 2016 Corvette Z06, 2018 GMC Sierra Denali 2500HD Diesel, 2021 Camaro RS
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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
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
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