Rear Differential Oil Volume

that would show up as a leak at ends of the axle by the seals and easy to find. But I dont think this is OP issue, it sounds like it could be underfilled

 

Ok. What's everybody using for oils? Is it the fairly rare 75W85 GL5 that is the Toyota recommended lubricant, or are you going with off the shelf (Valvoline, Amsoil, etc.), much less expensive 75W90? And, is there really that big of a difference anyway? Is it possible that Toyota uses 75W85 to meet fuel economy standards due to it being thinner? Hence the 30K change interval?

 

I wanted to use what Toyota recommends and went with Red Line 75W85 GL5.

 

That sludge is metal from the ring and pinion.
It sounds to me that perhaps the ring and pinion pattern may not be correct.

In that case frequent inspections would be warranted. I would have pulled the rear cover after the 1st indication that something was amiss.

I set up the depth incorrectly on a 14 bolt GM diff.

When I pulled the rear cover after the diff started howling, everything had "hair" clinging it.

 

ive used Mobil 1 75W90 synthetic in all 3 of my 4runners without issue. Walmart always has a good supply.

 

Oh sh!t, you are older than me. I guess I don't know it all. I'll keep changing my diff oil at 30K or sooner.

 

Don’t overthink it. Your gears don’t care what oil they are sitting in. Valvoline 75w90 in the bags works fine and the bags make it super easy to install.

 

what he said.
I used Mobil

 

That ship has sailed. I’ve got 73k miles on it now, so if she blows, she blows. The diff sings a little bit between 62-67 ish mph. Not super loud, but it’s always done it. It will be interesting to see what it looks like on the next oil change, which is coming up soon.

If it ends up wearing out early, I guess it’s an excuse to regear and get 34s lol.

 

Oh I'm not. I do think that auto manufacturers create a bit of fear in customers by telling them to use this "special" oil. They end up taking it to the dealership for the "special" oil, get overcharged for "special" oil, and in reality the oil comes out of a 55 gallon drum of 75W90. I'm a big fan of Valvoline. That bag invention is the greatest thing ever for filling diffs.

 

I used 85w140 LucasOil after regearing to 456. It was basically mandated by ECGS. It is thick as molasses.

 

Fill till oil drops from fill hole..