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GT350 Unidentified Oil Leak

11GT50

TMO Intermediate
77
58
Union, WA
I'm having trouble locating where this oil is coming from. It seems to be running down the side of the transmission - possibly along the gasket? I really can't tell. It's started to show up after the last couple track days I've done but doesn't show up after I've wiped it off and put several hundred street miles on it. I have noticed oil beginning to seep past the oil pan drain plug so it's possible it's coming from there. As a precaution, I am replacing the drain plug when I change the oil next week. Outside of that I'm not sure. Any thoughts?

It's definitely NOT coming from the oil pressure sensor. I've resealed and check it regularly.
 

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11GT50

TMO Intermediate
77
58
Union, WA
Not sure at all. In fact, I'm inclined to agree with you. Searching around a bit, it appears the case vent is an extended hose with the vent at the top of the bellhousing and appears directly above where the oil is coming from. I think the next thing to do is to check to see if the hose is properly connected.

 

11GT50

TMO Intermediate
77
58
Union, WA
It does appear to be coming from the vent. The hose is several inches long and difficult to access by hand. The vent itself is attached to a turkey baster style bulb and is located between the back of the intake manifold and firewall and appears to be intact. Question now is, what should I do about it? Should I extend the vent further or am I just masking a problem by doing that? The transmission shifts fine and I changed the fluid a few weeks ago and there was no obvious debris or anything of that nature in the oil when I drained it. Is this something that's indicative of a transmission issue or more of a consequence extended heavy use and high RPM driving? There are two track days left this season and I'm inclined to finish out the season and just keep an eye on the leak to make sure it doesn't get worse. After that I can either take it to the dealer or drop the transmission myself.
 

11GT50

TMO Intermediate
77
58
Union, WA
It's possible but I did have to clean it up a couple times before the oil change too. When I changed the oil I just filled it until ran out the fill hole and it ended up being pretty close to the 2.5qt called for. I'll run it next weekend and see what happens.
 

Bill Pemberton

0ld Ford Automotive Racing Terror
4,492
2,895
Blair, Nebraska
W2W Racing
20+ Years
I know my favorite Ford Tech at our store in Blair, Ne. has told me he has seen a few leaks like this because of an overfill. Since their is a tranny cooler on most of the GT 350s a tech may not factor in the lines/cooler may still have some fluid in them and just filling without a great drain could cause an overfill. The advice above is good and likely an overfill is the culprit?
 

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