TH 350 leaking
Thread Starter
4th Gear
Joined: Jan 2024
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TH 350 leaking
So I have a 79 vette, standard 350 small block, with a TH350, and on the bottom of the casing for the transmission it’s leaking fluid out of this hole. Is this a warning sign that something significant has happened to the transmission? I initially was just going to reseal it, but i’ve topped off the fluid and noticed it was still slipping a bit. Thanks for the help ahead of time.
Race Director
Joined: May 2006
Posts: 18,782
Likes: 2,597
So I have a 79 vette, standard 350 small block, with a TH350, and on the bottom of the casing for the transmission it’s leaking fluid out of this hole. Is this a warning sign that something significant has happened to the transmission? I initially was just going to reseal it, but i’ve topped off the fluid and noticed it was still slipping a bit. Thanks for the help ahead of time.
If the transmission is slipping try a fluid and filter change but that may not resolve the issue. Does the fluid smell burnt?
Le Mans Master
Joined: Sep 2002
Posts: 5,236
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From: Myrtle Beach SC
I believe he is referring to the bellhousing shield used with 350 THMs. It has a hole to allow "leaks" to seep through...warning the owner that a seal is leaking! My guess. 
Take the cover off and look up there where the transmission shaft plugs into the engine. Run the car first...then see what you've got to deal with. Several years ago, my 78 THM had leaks but and, after some study, determined it was confined to the THM pan. Other leaks were from high and the valve covers. However, I don't recall other holes in the transmission casing.
Take the cover off and look up there where the transmission shaft plugs into the engine. Run the car first...then see what you've got to deal with. Several years ago, my 78 THM had leaks but and, after some study, determined it was confined to the THM pan. Other leaks were from high and the valve covers. However, I don't recall other holes in the transmission casing.
