What's this leak?

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Apr 10, 2011
Longview, Texas
I have decent sized puddles of oil under my 1997 Land Cruiser every morning, a little bigger than saucer size. I looked under it and found a bit of oil where the transmission bell-housing bolts up to the engine. I cleaned that off with a rag and came back 20 minutes later, to find a drop of oil building up in/ under what I believe to be a breather hole there.

Is it the rear main seal? Something else? Should I be concerned and pull the trans to check it out, or just live with it for a while? I've done a few searches for rear main seals on here, but nobody has specified where exactly the oil drips from when those go bad, or how much is an acceptable amount. I've only had this vehicle since Friday, so I don't know how much oil it loses over a longer term.

Sounds like rear main seal to me
Sounds like it is leaking quite a bit as well
When I bought it, it had a fresh oil change from the dealer. They overfilled it a little bit and it still isn't to the normal level. I haven't messed with that because it seems like it is only a half quart or so high and I figured it would level out soon enough with the leak.

What are the chances of some heavier oil, such as 20w50, helping it out? I might drain it all and fill it with some new oil.

Also, is there anything else that could cause leakage through that hole?
Drain and fill with the correct amount of oil.
Where are you located, 20w-50 is pretty heavy
try 15w-40 first, and I would use conventional oil not synthetic just in case it really is leaking
Synthetic could make it leak worse
Sounds good. What are your thoughts on high mileage oils with "seal conditioners" such as Castrol GTX High Mileage?
I wouldn't think that the upper arch gasket would cause leaking through that hole... but I've only spent about 5 minutes under there so I could very well be wrong...

It's not a DD, so maybe I should bite the bullet and replace both if thicker oil doesn't fix it?
Is there a preferred vendor around here for OE FIPG and the OE rear crankshaft gasket?
Additionally, any idea what an A343F weighs?
1) CDan at American Toyota - killer prices on OEM parts, plus he knows the part number of nearly everything on an 80 by memory.
2) A lot
I just run....

Sounds good. What are your thoughts on high mileage oils with "seal conditioners" such as Castrol GTX High Mileage?
15W-40 for Diesel engines. Good stuff. I used to run 10W-30 synth but too many leaks. .02
I just bought a bunch of Rotella T 15w40. :D

I also pulled the cover off of the access hole and felt the rear crankshaft seal, which definitely is not uniform all the way around the bottom half that I could reach.

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