well you will always have the paste as the diff is continually wearing regardless of what fluid you use, and the drain plug is magnetic. The important thing is the quantity of the accumulation on the plug (aside from a used fluid analysis). The quantity shown by the OP in the pics of this thread shows a large amount of paste, it looks pretty thick.

When I first got my car it had Redline 75w90 in the diff and the plug looked pretty clean when I drained it, it had a thin layer of paste, almost opaque and didn't cover the entire plug diameter. When I drain my amsoii fill in the next while I'll be able to compare the appearance. I never had a used fluid analysis of the Redline so the only thing is to compare the accumulation on the mag. plug.

 

Just changed my diff fluid this afternoon (2005 Rio Yellow). Car had 15,680 miles at the time of change. I assume this was the factory fluid.

The oil looked very silvery and the layer of paste on BOTH plugs was rather heavy, especially the drain plug. I was kinda horrified.

Might some of the paste be a solid molybdenum anti-shock/anti-wear additive? I'm sure most of it was wear ... and most of THAT was break-in.

I'm trying Chevron's borate-chemistry 80W-90 right now. I will run that about 3,000-4,000 miles, dump it, refill with the same and run it about 10,000 miles then run a lab test on a sample to see how it is holding up.

 

I doubt Honda uses any such anti-shock additives in their gear oil, I'm betting what you are seeing is break-in wear, it should definitely be cleaner on the next run.

 

JFusion, I think you're right ... but don't dismiss the idea Honda might use just such an additive.

When they switched over most of their cars' engines to 5W-20 almost a decade ago, we were seeing UOAs on factory fill engine oil with astronomically high molybdenum (in soluble form) readings ... much higher than subsequent intervals with Honda OEM motor oil.

One of the obvious conclusions we drew is that the engines were filled with a special moly additive at the factory to ease break-in, especially when running new, extremely thin 5W-20 motor oils.

Just a thought.

 

I remember draining the OEM diff oil at around 5K miles. It was nasty stuff already and didn't really pour out. It plopped and globbed out. It was grayish black in color already, probably from sludging. It's good to get this stuff out early!

I always wondered why manufacturers don't specify a heat treatment cycle and early fluid changes while breaking in the final drive gears. The after market gear folks are very specific about this and consider it mandatory for warranty purposes.

There was a Honda News Bullletin posted here a few years ago that stated Honda didn't use a special break-in engine oil as a OEM fill. They said the moly content was from assembly lube.

 

It is just fine metal paste from wear. very normal.

I use Mobil1 75w90 on my car and all my customers. After 35k miles, I drain it and the stuff comes out like brand new.

The magnet in the plug is so clean, you can see it. Metal paste is almost non-existent.

 

"There was a Honda News Bullletin posted here a few years ago that stated Honda didn't use a special break-in engine oil as a OEM fill. They said the moly content was from assembly lube."

Thanks INDYMAC, but I think it's 6 of one, half a dozen of another. Whether the extra moly comes from a factory additive or assembly lube ... it's extra moly they add at the factory. See what I'm getting at?

Good to know, Billman250. I'm not a big fan of Mobil 1 oils in general. They're not bad but I think they could be better ... but it's hard to argue with gear oil that drains out looking clean.

We'll see how my Chevron holds up. With 3 more quarts on hand, I have enough to last at least 3-4 years even assuming fairly short intervals.

I have only had my car 6 weeks. I'm still not sure how many miles I'll be putting on it per year ... I expect 5,000-6,000.

 

I also say it's totally normal. I just did a diff oil change yesterday and saw the exact thing on the magnet of the drain plug. And, I've seen it before when I've done the diff oil change.