Automatic transmission vent hose
- Thread starter OilUzer
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the dip stick is the vent (if it has one)
There has to be one otherwise pressure would build up inside the transmission. And yes, there is usually a valve of some sorts, usually just keeps the bigger schmoo out.
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My Accord has one on top next to the dipstick with a rubber cap on it.
No, some are open vents example GM 4L60 and 4L80, some have check valves in the vent caps example Ford 6R80!
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My new Buick(Opel) has the vents for the transmission and AWD transfer case zip-tied to the coolant bottle.
![[Linked Image]](https://www.bobistheoilguy.com/forums/attachments/usergals/2019/09/full-53735-36220-img_0924.jpg "[Linked Image]")
It is a must. My dad's 01 Taurus had a huge amount of ATF burped on the garage floor, because the vent is too short and was stuck. TSB said pull the old one out and hammer in a barb and use hoses to build a snorkel to the top. It works fine ever since, no more burping.
The front diff vent tube fell off its wheel well post in my 06 Escalade during winter. A months worth of cooling down and warming up cycles sucked in enough salt water and sand to grenade the diff. So yeah, breathers are critical.
I just recently checked the Vents for the Transmission and Rear Differential .
Transmission: Has a (weak) spring loaded cover. I cleaned around it / all looked good
Rear Differential: I replaced the Hose and added a Filter (just to block any dirt)
![[Linked Image]](https://www.bobistheoilguy.com/forums/attachments/usergals/2019/09/full-79675-36234-100_0148_li_2.jpg "[Linked Image]")
Transmission: Has a (weak) spring loaded cover. I cleaned around it / all looked good
Rear Differential: I replaced the Hose and added a Filter (just to block any dirt)
Originally Posted by PandaBear
It is a must. My dad's 01 Taurus had a huge amount of ATF burped on the garage floor, because the vent is too short and was stuck. ...
A must for manual transmissions and transaxles, too.
When I had a shop replace the noisy bearings in my Mazda's manual transmission, they used different oil than Mazda specified. I'm not sure the oil difference was the whole reason, but after the repair, the transmission persistently burped oil out the stubby vent pipe on top---even when low on oil. After various unsuccessful attempts to stop the spillage, I stopped it by attaching a vertical section of fuel-line hose nearly up to the hood, with a fuel filter in the middle.
It is a must. My dad's 01 Taurus had a huge amount of ATF burped on the garage floor, because the vent is too short and was stuck. ...
A must for manual transmissions and transaxles, too.
When I had a shop replace the noisy bearings in my Mazda's manual transmission, they used different oil than Mazda specified. I'm not sure the oil difference was the whole reason, but after the repair, the transmission persistently burped oil out the stubby vent pipe on top---even when low on oil. After various unsuccessful attempts to stop the spillage, I stopped it by attaching a vertical section of fuel-line hose nearly up to the hood, with a fuel filter in the middle.
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