Oil on inside of rear rims

My dad has a 2006 or 2007 PreRunner and there is oil on the inside of both of his rear rims. Does anyone know what could cause this and roughly what a shop would charge to fix it?

 

Did he check for leaks? Maybe he drove through some oil?

 

I climbed under there and looked and it was only on the inside of the rims. Didn't look like he drove through it.

 

Is it oil or could it be brake fluid?

 

Could possibly be the axle seals..something that both of you can tackle in a day if you have the proper tools

 

Or it could be cat or dog spray... has happened before lol

 

First thing I asked him is if he had pissed on his rear tire..until i climbed down there and looked at it.

 

Not sure. It looked greenish black..not red.

 

Axles seal me thinks!!!

 

did you happen to see if one of his rear shocks is leaking? Just a possibility.

 

Smell it, if it smells like shit its gear lube which means axle seals.

 

Axle seals. I had three replaced under warranty. There was something that they found that was abrading the seals that they ground off. Pull a wheel and brake drum and you'll find out more.

Not sure if this applies but on fords that I had owned a bad bearing was usually the cause off seal failure so if you have a lot of miles it's probably best to replace the bearings.

 

This. Both sides? Did he drive through a puddle lately?

 

I didn't see any oil near the shocks and I don't think he went through any puddles..deep ones at least.

Thanks for the help everyone.

 

AFAIK, until you do this ^^^^, you're only guessing at what's going on.