Rear Diff leak?

Can anyone suggest how to begin troubleshooting this apparent leak?

 

Check the diff fill plug for torque, probably the last person to check the diff fluid (did you get an oil change recently?) topped it off and spilled some. Or the crush washer could be missing. It probably not an actual oil leak as the oil level is below the plug.

 

I did get the oil changed a few weeks ago. I decided to crawl under today to see if I need to do a pressure wash and that's when I noticed the oil saturation

 

Pressure wash it off, and see if the oil returns. It it does. You got a leak. If not, you don’t got a leak

 

There's a tsb for leaking rears

 

There is, but it's not generally related to that area on the housing - rather it's usually associated with the carrier gasket/bolts on the other side. If OP wants to have it checked anyway, well that is of course his decision.

I agree with the guys saying it has something to do with the fill plug/washer.

Edit: If this started after dealer maintenance, I'd definitely bring it up with them. Not that I couldn't fix it myself - it's the principle of the matter. Dealer shouldn't be making things worse by doing routine checks.

 

Or new crush not used.

 

I wouldn't open and check it just bring it to the dealer and tell them you seen the rear leaking on your drive way. I did that and they gave me a new rear end.

 

I had that rear diff seal replacement TSB done on my truck. If you compare your photo to mine below, you can see there is a difference. If you can provide another shot of the diff seal area (like in my images) it may make it easier to determine. As a layman, it visually appears that your fill nut may be loose and/or the crush washer is damaged/wasn't replaced when changing the fluid. If you have not had your rear diff touched since purchase, then you should bring it into Toyota.

If you had a 3rd party mechanic change the fluid, then bring it back to them. If you changed the fluid yourself, then I'd recommend three things before you bring it into Toyota or a mechanic.

1. Tighten the fill nut to torque spec, spec should be in the owner's manual.
2. Degrease and clean the entire diff housing until you no longer see the stains.
3. With continuing your normal driving routines, wait a day, two or more and check again. If still weeping/leaking, then bring it in.

Here are two images from my truck's weepng diff seal for comparison to your image.

 

Another for good measure

 

I appreciate the quick responses! I got the oil changed a few weeks ago in Wyoming on my cross country journey. It was done by a franchise called Grease Monkey. they did check the fluid levels and more than likely did not replace the crush. I cleaned the area and I did not see any oil residue near the seal. it's only around the rear facing side around the plug. Hopefully it's just a messy job by the goofs who checked the fluids.

 

Anyone have the part # for the crush washer?

 

If you just want this one, it's Toyota P/N

$12 12157-10010 Toyota Oil Drain Plug Crushable Steel Gaskets Set of 10 OEM 12157-10010

12157-10010.