Diff weep hole: can I RTV this?
Thread Starter
Safety Car
Joined: Sep 2002
Posts: 4,030
Likes: 6
From: Maryland
Diff weep hole: can I RTV this?
Hi,
I noticed recently a tiny drip of what I am 100% certain is diff fluid at the trans/diff interface area on the bottom side of the diff. I get about 1-2 drops every 300 mi driving; it never drops on the garage floor.
I think the drip is coming from the little weep hole on the diff near where the tranny mates(based on the drip spot). This is little hole is on the underside of the car; hard to spot unless on a lift. Axle seals dry as a bone and were recently done. I have to check to make sure diff is not over filled from when this work was done (shop) but I don't think so; shop is pretty good.
So my question: Can I just RTV that weep hole shut? Just as a diagnostic to see if this is the drip source? I assume doing so would keep the diff fluid where it is and the trans fluid is not dripping at all so no change there. Has anyone done this?
Did lots of seaching but seems most have tranny significant leaks where the tranny mates to the diff, mine is diff. fluid and so small it's hard to find.
Thanks,
Andy
I noticed recently a tiny drip of what I am 100% certain is diff fluid at the trans/diff interface area on the bottom side of the diff. I get about 1-2 drops every 300 mi driving; it never drops on the garage floor.
I think the drip is coming from the little weep hole on the diff near where the tranny mates(based on the drip spot). This is little hole is on the underside of the car; hard to spot unless on a lift. Axle seals dry as a bone and were recently done. I have to check to make sure diff is not over filled from when this work was done (shop) but I don't think so; shop is pretty good.
So my question: Can I just RTV that weep hole shut? Just as a diagnostic to see if this is the drip source? I assume doing so would keep the diff fluid where it is and the trans fluid is not dripping at all so no change there. Has anyone done this?
Did lots of seaching but seems most have tranny significant leaks where the tranny mates to the diff, mine is diff. fluid and so small it's hard to find.
Thanks,
Andy
Instructor
Joined: Feb 2012
Posts: 105
Likes: 0
From: Acworth Georgia
As long as you aren't referring to the breather on top of the diff, then yes RTV won't cause any harm. It should stop the leak as fluid in the diff isn't under pressure so long as the breather is not clogged up top.
Thread Starter
Safety Car
Joined: Sep 2002
Posts: 4,030
Likes: 6
From: Maryland
From my reading, the weep hole is for diagnosis of a leak in the diff seal where it meet the trans or the trans seal...there's a little area between and this has the weep hole. So if I seal it...and the diff O-ring is letting a little oil past it...is it reasonable to assume pressure will build once the cavity is full and force the diff fluid not to escape the diff O-ring? Only issue I see is that the trans seal would have to stay tight.
Is there any reason this weep hole would be used for pressure relief or anything like that?
Thanks
Supporting Vendor
Joined: Apr 2011
Posts: 3,332
Likes: 195
From: Frederick Maryland
St. Jude Donor '08-'09-'10-'11-'12, '14-'15-'16-'17-'18
The tailshaft housing houses the inner and outer seals. The inner seal hold the trans fluid in and the outter seal holds diff fluid in. There is a cavity in between the 2 seals. That cavity is is drilled and the the peep hole is the exit. If you see diff fluid coming from it, that means the outter seal is leaking. You have to remove the differential to service that seal.
__________________
Thread Starter
Safety Car
Joined: Sep 2002
Posts: 4,030
Likes: 6
From: Maryland
The tailshaft housing houses the inner and outer seals. The inner seal hold the trans fluid in and the outter seal holds diff fluid in. There is a cavity in between the 2 seals. That cavity is is drilled and the the peep hole is the exit. If you see diff fluid coming from it, that means the outter seal is leaking. You have to remove the differential to service that seal.
Melting Slicks
Joined: Apr 2008
Posts: 2,343
Likes: 9
From: Lexington Park MD
Based on Rick@RKT56's response it sounds like you DON'T want to seal up that hole so that you will know if the leak gets worse. You said yourself the hole is for inspection of the seals, why would you want to plug it up when it is doing its job and telling you that you have a tiny leak on the diff side?
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Instructor
Joined: Feb 2012
Posts: 105
Likes: 0
From: Acworth Georgia
Based on Rick@RKT56's response it sounds like you DON'T want to seal up that hole so that you will know if the leak gets worse. You said yourself the hole is for inspection of the seals, why would you want to plug it up when it is doing its job and telling you that you have a tiny leak on the diff side?
I see no harm in patching the hole temporarily, as pulling the diff isn't an everyday repair and a weeping seal isn't a catastrophic failure. As long as fluid levels are checked regularly, and this issue isn't ignored for an extended period of time, I say go for it!
I wouldn't want gear oil dripping in my garage, one drop of used gear oil will saturate everything in there with its horrible stench!
Supporting Vendor
Joined: Apr 2011
Posts: 3,332
Likes: 195
From: Frederick Maryland
St. Jude Donor '08-'09-'10-'11-'12, '14-'15-'16-'17-'18
Temporary patch would be ok but long term might not be adviseable. If you have the cavity filled with oil it might seep into the trans in worse case.
Thread Starter
Safety Car
Joined: Sep 2002
Posts: 4,030
Likes: 6
From: Maryland
Thanks everyone for the replies! Glad to here this might be possible as a temporary diagnostic tool. From your experiences, can I assume there is no pressure relief function for this weep hole? It strictly exists to tell the user that there is an internal leak of 1 of the 2 seals?
