Drum brake replacement turned into much more

I have scoured the search function and really can't figure this out. last week I was changing out rear brake shoes. The reason I was doing this is (a. my dash brake light was on, (b. the front wheels where almost black with brake dust...I read somewhere that's an indication that rear brakes aren't doing their part, (c. I had changed the front rotors and pads and brakes still felt like they were slipping.
I started with the passenger side, besides having to beat the drum (haha) I really had no issues with that side. Got to the other side and there is quite a bit of grease...well it looked like grease to me. Luckily someone was there with me that knew a bit about cars. I would have wiped it off and changed the shoes and been done. He tells me that I have an axle seal leak. That all of that is gear oil. Decide not to change those shoes. We discuss about getting the dealership to do it or doing it ourselves. He look over the manual and not too complicated. I get home and start looking through forums. I have a few questions. Does gear oil when it heats up turn into grease? There were distinct gobs of grease. Wouldn't my differential be low on gear oil? Approximately if it is a bad seal, what does the repair shop charge, I have read of the nightmares on this forum. Could it be wheel bearing grease?...Any direction wold be greatly appreciated

 

If the seal is bad it lets gear oil into the bearing and from the bearing spinning in oil it can fling out some of its grease. Also the gear oil tends to mix with the brake dust and can glob up too. The alldata labor time shows 2.9 labor time. So at least $300 in shop labor plus parts. The seal itself is about $8 and here is the part number 9031058003. You'll need to drain the rear diff and when done fill with new fluid. Don't reuse if you do it yourself. The diff fluid will cost a bit, also recommend a few can of brake clean to help with the mess.

 

Edit sorry thought you were a second gen truck.

Alldata labor time for 2002 Tacoma Double Cab 4x4 is 1.7hrs for one side.

Listed are 2 rear axle seals, a inner and an outer.

Inner - 9031050006 - $6.98
Outer - 9031354001 - $13.39

 

well that's not too bad, I do appreciate your insight, makes sense with diff fluid, and dust

 

Replacing the inner seal is pretty easy, but the outer seal is pressed on with the wheel bearing, so you'll probably have to take the axle and backing plate assembly in to get pressed off and a new bearing and outer seal pressed back on.

Or you could just replace the inner axle seal and clean out your brake drum and replace the shoes and call it good, then hope that the leak stops.

 

The brake warning light comes on when the brake fluid level is low, or the brake is on.... So despite your new problem you may have low brakes up front also, I'd check them

 

I had changed the front pads and rotor already to stop a squeal, but they were still slipping a bit and the brake light remained on, which I knew was the emergency, cause when I would messed with the e0brake handle it would flash