About 600 miles ago I changed diff fluid to AMSOIL. A week later I picked up a nail and lost tire pressure but didn't notice anything while driving about 40 miles. I refilled the tire and drove home (replaced rear tires the next day). I now observe there is a growling noise at low speed tight turns to the right (same side the tire went flat). I'm wondering if I damaged the LSD/rear end by drivingon the low/flat tire? Any suggestions?

 

1. Amsoil what?
2. 40 miles is a long way to drive on a tire that isn't it's full diameter. That's why they say to never put the spare on the rear. It may cause damage to the LSD.

 

I wouldn't mention the flat to the dealer because they will likely deny you a warranty fix.

 

Totally my fault - I felt the car pull when I stepped on or let off of the gas so I knew it was low. I just didn't think it was flat. I'm not even going to try to get the dealer to fix it as it was not caused by anything other than my incorrect thinking that I'd take care of it later....
I did check the lug nuts and tightend them to 82 f # - that seems to have reduced the noise. I tried making slow left and right circles in a parking lot this morning and found that the noise occurs in both directions when I start from a start so maybe it's normal...
BTW xviper it's the recommended 75-90 wt gear lube from AMSOIL.

 

take it to the dealership and plead ignorance and they should replace it under warranty.

 

Why - I know why it's broken (it if is) - I did it....

 

It is very refreshing to see someone as honest as you.
However, what JSWhaler is suggesting is not cheating or lying. It's worth a try. If they don't cut you a break, then you can decide if you want to fix it or not. You can always just change the fluid and continue driving it till it starts to make more noise. What's done is done. It won't get better, but you may luck out and it won't get any worse, either. I would suggest you try something a little more heavy duty like the LE607 fluid. Amsoil and Mobil 1 are good, but it might be time to try a single wt. fluid now. It might just help.

 

Lets NOT forget to mention that Honda recommends SAE 90 / GL-5 hypoid gear oil in the S2000 differential.
With NO exceptions

xviper vs Honda ?????



Anyway..
A bit of noise during tight turns isn't that wierd or a really big problem IMO.
Even if it started doing it after driving like the OP posted.
Your planetary & side gears and side & center washers got a bit of a work-out.
As long as the diff works properly on tight turns (or any turn) you're ok IMO.

Like xviper suggested give LE-607 a try.
Do not expect miracles.

 

Not me. I would never go against the recommendations of Honda. Remember, I'm the one who always tells people to "read the manual". It's just that every once in a while, Honda does make some odd statements.
One such example is to only operate the soft top when the engine is not running.
The other one is that they recommend a diff fluid that Honda car division does not have. They (and we) would have to go outside of their division to get it.
Your discovery of the Honda marine division fluid was a great find. And we all know that Honda Canada goes to their motorcycle division for diff fluid used here.
Personally, I would go with either of the Honda fluids before I'd go with the LE607, but this is a unique circumstance where the known thickness of the LE might just do the trick.
I'm a firm believer of "If it ain't broke, don't fix it". However, in this case, something may be broke.

 

The rolling diameter of a steel belted radial does not really change that much, even when severley under inflated. Besides, if that caused the LSD to fail, then we would all have to dirve on straight roads to "protect" these fragile parts from any difference i rotation speeds.