Jewjenk

Changed out my diff oil today, put Royal Purple in.

The old oil was as black as 10,000 mile motor oil, car is 2000 auto with 20,500 miles there was fine particles on the magnetic drain plug, nothing to be scared about. Never saw original oil in unused shape, just wondering if this was normal.

3musky3

factory fill is basicly synthetic gear oil with friction modifier already in it

ubnpast

What weight did you put in, 75-90? Did you put the friction modifier in also?

I need to put that on my list of things to do.

bumble-z

Normal for the old gear oil to be black in color at change out.
You didn't mention the color of the fresh Royal Purple you put in.
Redline diff fluid is golden/brownish in color,as is Amsoil , when fresh.

vettenuts

When I used Amsoil it was a blue color. My original swap was dark but not black. Last time I drained the Amsoil it was still blue, but the differential had some miles on it at that point. The DTE build I now run requires a special blend of Redline.

Cybermind

Changed out my original diff oil at 30K miles. It was light brown in color and appeared to be in good shape. I was pretty surprised and relieved since I had just purchased the car. I replaced it with GM synthetic diff fluid and additive.

So, to answer your question; it all depends on how it was driven.

Jewjenk

Royal Purple = PURPLE

Jewjenk

I usually drive very conservative. But I can't testify that for the car's 1st 15,000mi before I brought it.

Jewjenk

Royal Purple comes with the modifier already in the oil and it was 75-90.
Funny how the old oil seemed thin.


To all -------------------- Thanks for answer's and concerns. The reason I changed the oil, was that it has the leaky butt, only a few drops here and there. Wanted to make sure the diff was at full level and have read before that someone had changed their oil and the leaky butt stopped. So now I have a full diff and hope that the seals will swell and stop the leak or I will be repairing it manually.

bumble-z

Really!?

Old Horsepower

Changed mine last year. It just kind of looked like used motor oil. Bought Vette used with 50K miles. Have no idea if it had ever been changed. Is there a schedule for this? Put in Mobile 1 synthetic that already has the additive in it. The Mobile 1 was clear. No color.

johnson-rod

I don't remember what color it was but I sure remember how it smelled!

Jewjenk

Yeah, my wife is still complaining about the smell in the garage....

sgancarz

I have a DTE Stage II Diff that only has 5,000 miles on it, however it was installed 7 years ago. Invoice shows Redline 75-90W Synthetic was installed w/Additive. Anyone think that oil has degraded to the point of being the source of differential noise?

leadfoot4

Just my $02.2 worth....I always thought that GM puts some sort of moly lube in their diffs, in order to help break in the gears. This is what makes the oil so dark in color.

I've always changed the diff oil in my cars every couple of years, and noticed that the first drain (after 6-8000 miles) looks like bad-azz motor oil, the second change is a LOT cleaner, and I recently stopped changing it after a 3rd change, because A) gear oil is getting more expensive, especiallt the syn oil; and B) after 3 changes the stuff comes out clean, no matter how many miles....

Jewjenk

Now that makes sense, thanks..