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What could be the cause of this transmission fluid leak?
Heyy guys, just wanted to get your say on what could be causing this leak. Whenever i park over night, i see a few drops of leaked ATF. As seen in the photo below, i decided to take a photo before a cold start this morning and yeah there is an obvious leak. I hope someone has an idea on the cause of the leak.
It appears to be coming from that pan just to the right. Is that your transmission pan? What year car is this? Those pan bolts are supposed to be 69 in lbs.
It appears to be coming from that pan just to the right. Is that your transmission pan? What year car is this? Those pan bolts are supposed to be 69 in lbs.
Yes, thats my transmission pan. Its a 2004 Es330. Probably a few loose bolts you think? I am really curious, because the same is happening with my engine oil too. I will try tightening them up and see if the leak stops. Thanks
Loose bolts is probably worth a try. The transmission isn’t operating in some high pressure environment, so it’s more than likely loose bolts. I believe they’re worth an annual check as well as valve cover gaskets among a few others.
Clean it up good when you’re done and keep an eye on it.
Loose bolts is probably worth a try. The transmission isn’t operating in some high pressure environment, so it’s more than likely loose bolts. I believe they’re worth an annual check as well as valve cover gaskets among a few others.
Clean it up good when you’re done and keep an eye on it.
Definitely wasn't the case of loose bolts. The leak was coming from the seal/gasket for the oil sump. Since the leak is minimal i will just wait till my next oil change thats like 800 miles away and get it done with. But i am still curious why both seals/ gaskets for both the transmission and engine oil sump would leak at the same time.
The number one killer of engine gaskets is the notoriously often-overlooked and very important PCV valve. Bar none. 40% of car owners never check their PCV valve in spite of it’s failure means that major issues can and do cause problems. Another 38% said once a year. If your engine oil is coming from your oil sump gasket and your bolts are tight, you’re in for a gasket change soon or your engine will suffer the pangs of vacuum problems. Denso PCV valves are $10 online.
I was in gross error concerning transmission atmosphere and pressure. Changes in pressure is what makes it operate, etc. High pressures. The atmosphere at the sump, though might be around 3psi(?), hence your leak.
Today’s automatic transmissions use the vacuum pressure of the engine to help decide what gear they’re going to operate in and whether it’s Wide Open Throttle or whatever. Whether the erroneous vacuum data would affect the transmission isn’t debatable, but whether it would “blow out” a sump gasket is an open question.
BTW, the last item I changed in the hunt to cure my ‘02 - ‘06 ES transmission gear changing problem was my PCV valve even though the old one sucked and blew accordingly.
Years ago automatic transmissions utilized vacuum modulators. I believe newer computerized vehicles uses sensors on the engine and transmission to detect such things as throttle position, vehicle speed, engine speed, engine load to determine gear selection.
And if the PCV valve is stuck closed, open or otherwise not operating correctly, the throttle position, vehicle speed,engine speed and engine load sensors will not operate correctly. Yes, the vacuum modulators are from days of yore, but the same premise applies.
Besides, I wasn’t saying the PCV valve was the cause of the sump leak/gasket blown out. Just that it would affect shifting.
Last edited by Richardsr; 11-20-19 at 07:20 AM.
Reason: Info
The number one killer of engine gaskets is the notoriously often-overlooked and very important PCV valve. Bar none. 40% of car owners never check their PCV valve in spite of it’s failure means that major issues can and do cause problems. Another 38% said once a year. If your engine oil is coming from your oil sump gasket and your bolts are tight, you’re in for a gasket change soon or your engine will suffer the pangs of vacuum problems. Denso PCV valves are $10 online.
I was in gross error concerning transmission atmosphere and pressure. Changes in pressure is what makes it operate, etc. High pressures. The atmosphere at the sump, though might be around 3psi(?), hence your leak.
Today’s automatic transmissions use the vacuum pressure of the engine to help decide what gear they’re going to operate in and whether it’s Wide Open Throttle or whatever. Whether the erroneous vacuum data would affect the transmission isn’t debatable, but whether it would “blow out” a sump gasket is an open question.
BTW, the last item I changed in the hunt to cure my ‘02 - ‘06 ES transmission gear changing problem was my PCV valve even though the old one sucked and blew accordingly.
11-17-19, 11:21 AM
What could be the cause of this transmission fluid leak?
