Diff Fluid Condition

[Miles69]

I hope this is not just another stupid question, But I changed all my fluids this weekend and noticed that I had a good bit of metal on the magnet in the diff, and the fluid was a very dark gray like graphite. I only have 15k on the car. Is this normal?

Thanks in advance for the help.

[bimdub]

honestly? first change of fluid, yeah it probably is completely normal, there is some break in going on in there, and this is likely to shed some metal, and certainly could be a what appears to be a lot. as for the fluid, 15K is the life of the fluid so dark color is expected as well......

[My_yella_s2k]

the metal you seeis just the diff particals. the 1st one is the worst, thn it gets better but it is always present.
the gray is the clutches slipping, and burning off... your ok. :D

[CMan]

Gonna agree with everyone else too. The first change is the worst. It's from all the breaking in. In fact, some say it's a good idea to do your first diff fluid chance around 3,000 miles. I've had 2 S's, the first I changed the diff fluid at 15K and the second at 3K. Both times the fluid was dark and there was a good amount of shavings.

[Miles69]

Thanks for the replies. That's what I was thinking, but just wanted to verify. since it is easy to change I'll do it aging in 5K then every 10k. Is there any advantage to using 75-140 over the 75-90w? I drive pretty hard, but no track time yet.

[batguano]

Thanks for the replies. That's what I was thinking, but just wanted to verify. since it is easy to change I'll do it aging in 5K then every 10k. Is there any advantage to using 75-140 over the 75-90w? I drive pretty hard, but no track time yet.


I'm using 75-140 in mine and I am pleased with it. I run Richmond 456 gears and it seems to be quieter with the 75-140. My thinking is, if you are going to track the car, use the 75-140.:)

[repiv]

What you see is pretty normal:
http://inlinethumb54.webshots.com/40309/2750350570025981935S600x600Q85.jpg (http://good-times.webshots.com/photo/2750350570025981935TicnjZ)

As for the magnet, that too, is normal so long as there aren't any distinct pieces of metal. Here is one of my early diff fluid changes. The black streak is what came off the magnet on one "sweep":
http://inlinethumb52.webshots.com/41331/2865630060025981935S600x600Q85.jpg (http://good-times.webshots.com/photo/2865630060025981935XDINXg)

I change mine out annually or every 10K to 15K. I've been using Mobil 1 75W90 for years in the S2000, but this year, I went to 75W140 Quaker State because it's hard for me to find M1. So far so good.

[Miles69]

Thanks for all the replies. That is just what I saw Repiv. Tranny fluid looked new after 15K but as I now see the rear diff takes a beating. I feel better, but I thinl I'll change it every other oil change ~10K.
Thanks again.

[repiv]

Tranny fluid exists under much different conditions and will look like new even after 100K. The gears in the tranny are cut differently than those in the ring and pinion of the rear diff. They also share the load with many other gears. In addition, the tranny has a fluid pump, which helps to circulate the fluid where it can release some heat via the casing fins. Nevertheless, even tranny fluids can degenerate long before it ever looks bad. I change mine every other year. However, if the car is tracked or driven under harsh conditions, more frequent changes are advised.

PS. Our rear diffs don't have clutches. The Torsen Limited Slip utilizes a system of worm gears.