Where is this leak coming from?

[jminz]

Does your mystery fluid feel oily? What does it smell like?

Interesting that I've had a somewhat similar, intermittent issue with a "class I" leak (formation of a drip/wetness) in the same spot as your second pic (RT side front diff). I've been thinking I had a very, very slight gear oil leak from my passenger side CV at the diff from the axle seal. I can't really tell the color but I'd say it looks kind of yellow like your pic of your garage floor (but I've never had any puddles like that, nor evidence of any leak collecting on the top side of my rock shield). It looks like gear oil, and it feels kind of greasy/oily (but the other day I saw a slight beginnings of a drip, felt slick but didn't have the distinctive smell of gear oil).

Its weird, I've not been able to see evidence of the leak at the edge of the diff housing where the CV axle dust cove meets near the housing... where I'd expect it to be coming from. I've briefly looked to see if it might be coming from somewhere else, though I'm virtually 100% (99.99999999) sure it's not coolant in my case. I have no issues with my coolant/radiator/etc... I guess I'll look around my valve covers for any evidence...

See the link I posted in post 13. Check that area for leak.

 

[rattlesnake]

You should be using a coolant that meets the following specifications:

-Ethylene-Glycol based
-Non-Silicate
-Non-Amine
-Non-Nitrate
-Non-Borate
-HOATs (Hybrid Organic Acid Technology)

The following coolants meet the above specifications based on some research:

-Genuine Toyota SLLC (Super Long Life Coolant) aka "Toyota Pink" (Do not confuse this with the "Toyota Red" Long Life Coolant, they are two different formulas)

-Amsoil's Coolant

-Zerex Asian Formula

Thank you very much for this info. I'm getting ready to do a drain/refill since the mechanic I had my truck at replaced the coolant with random green stuff. Quick question though... If they both meet Toyota's requirements, why would anyone buy the Toyota Pink at ~$25 a gallon when you can get the Zerex Asian Formula for ~$15 a gallon? Not trying to be difficult, just an honest question.

 

[Sungod]

Most likely it is brownish from running down some pretty nasty shit. Get some degreaser and spray the area down to clean it off and dry it out. If it is coolant, it won't just evaporate sitting there.