Hello. So, I just serviced my front diff, and the drain plug had a ton of, what can only be described as "gunk" on it. It looked and felt like putty. The actual gear oil that poured out honestly didn't look too bad, so I'm wondering what the deal is. I serviced the diff (not quite due yet) because there's been a whining noise coming from the front end (as best I can tell), that sounds kind of like when they sharpen a sword against a grinding wheel on Game of Thrones. No rhyme or reason to it as far as being acceleration related etc. but, the whine is still there after the new gear oil, and now a vibration has turned up. I used 80-90 oil btw. Any thoughts as to the whining noise, gunk on the drain plug, or anything?

Thanks!

 

The metallic gunk on the drain plug is normal. If you start to find hard metal pieces on the magnet, then you will be in trouble.
The 80/90 oil is good but I tend to use the thicker 85/140 oil in both diffs and transfer box.
I can't say much about the whining noise though. Did you check your diff's breather tubes?

 

I haven't checked the breather tubes, but took today off for a little rover focusing. What would checking them consist of? I mean... I know they're still there haha. I use the 85-140 in the t-case, but it's so damn thick and hard to pump in, I figured I'd go with the 80-90 on the diffs. I don't do much off-roading, so I figured that would be alright. Maybe I should beef it up though.

My other thought on the whining is the power steering pump. I have a slooooow leak at the reservoir I've been putting off dealing with. The level is just a hair below the low mark, but maybe that's enough for the pump to act up? It's tough to pin-point where the sound is coming from.