s2killlin

Long story short, I've been out to a few track events since the last time I changed my diff fluid and I think I set myself up for failure by using Royal Purple in a lighter weight than what I'm seeing what is being recommended. After my last event I got a clunking noise coming from my diff that is relative to speed so the faster I go the faster the "clunk" goes. I am going to drain the fluid, make sure there are no large pieces of metal in the fluid and then fill it back up with Amsoil 75-110 or 75-140.

Questions: When I have the rear wheels jacked up and off the ground and I spin one wheel the other wheel kind of spins but if I were to stop it from spinning it wouldn't take any effort. Is that a sign the diff is toast or is that the normal characteristic of our LSD? Also do you think changing the fluid going to be a sufficient band-aid for a short time until I can either rebuild the diff or get a new one? BTW this is a dedicated track car so there is no daily driving going on in between events.

Thanks in advance for any helpful responses.

s2killlin

Drained the fluid. Looks like my diff turned itself into a blender.

Rebuild, replace with ap1 or replace with ap2? Or upgrade?

flanders

What weight was the RP oil that you used?

s2killlin

Opie Oils

Do you know which oil specifically from the RP range it was? I am no real fan of RP but 75w-90 as a viscosity will not cause the diff to eat itself, we have many S2000 in the UK doing track days on 75w-90 without issue. Do you know what fluid was in it before the Royal Purple?

Cheers,

Guy

s2killlin

I was using RP 75w-90 Max Gear.

Unfortunately I don't know. The owner before me didn't seem to do the best job of caring aesthetically for the car and I bought it knowing that, but mechanically everything seemed to be up to par so. He had said he went to Honda for the transmission and diff fluid changes so whatever they were using but who knows how truthful he, especially not having papers to back it up. When I got the car I switched the diff fluid to RP 75w-90 Max Gear and kept the Honda trans fluid. I think I will be fully switching over to Amsoil after I figure out what to do in this situation.

Still curious what people would recommend my next move to be for either just replacing the diff, changing to an ap2 diff or going Puddymod? I pm'd Puddy but haven't heard back yet.. If anyone knows a better way to contact him please share!

Chuck S

I believe genuine Honda differential fluid will eat our differentials -- it's designed for their front wheel drive cars. At least that was the warning a couple of years ago with claims dealers had no clue the S2000 was different and requires GL5 gear oil. Tracking down what was used in the last "dealer service" is possible as these records are typically digitized and stored. If you can contact the former owner he should know where the service was done.

Assuming no dealer fix the easiest/best solution appears to me to be a swap for a used differential. They're common on eBay.

-- Chuck

flanders

Honda has a SAE90 GL5 diff fluid, they also have a lot of other fluids.
If you use the wrong ones which seems to have happened a few times then yes the diff will take damage, but the correct one is perfectly fine to use.
For the OP, I would put some new fluid in there and see how it works, maybe drain in after some short use and see if more stuff comes out.
The black smudge on the magnet doesn't look that bad but those loose metal parts does raise more concern.
Hopefully some expert here might have an idea where they might have come from.

SpitfireS

Those bits look like they came from the outer diameter of the ring gear.
AFAIK the pinion doesn't have the fillet / rounded edges.
So that's not good.
The pinion is most likely damaged too.
The fact it didn't go BOOM means the damage is still relatively small but I don't think you can trust it anymore (I wouldn't)
Are there any other bigger metal parts and are they softer, malleable metal and not black / brittle?

IMO this diff is done, sorry.

s2killlin