No reviews came up with a search so I want to know anyone's first hand knowledge running Castrol's syntrax 75w-90 limited slip gear oil? Any help would be appreciated.

 

I've been running Castrol SAF XO for a few years now and it seems fine. XO is for non-limited slip diff's which is fine because the S2000's torsen limited slip diff is just gears without any friction parts.

 

I use Amzoil in mine

 

Reporting back after 1 year, 2 track days, and 3000 miles. It didn't protect OR it was contaminated from dirty diff case and residual dirty oil. The diff has 62000 miles on it and I have no record of a diff oil change. Plenty of records for engine oil and tranny oil though.

 

Those wear numbers are really high, but like you said it could be cleaning of residual deposits within the diff case if the previous owner didn't do regular fluid changes. If the fluid came out dark in appearance then I would say it was cleaning out sludge/deposits within the diff case, because it would normally be pretty clear with a short run like that. You must have had a large pile of wear paste on the drain plug magnet ?. Very hard to tell.

On the other side I am proponent of thicker diff fluids, and I believe thicker means less wear when it comes to our diffs, as long as you don't drive in frigid conditions and depending on your location. I would only run a 75w110, 75w140, or SAE110 (LE1605). I'v posted my diff fluid runs on this site in the past, here is a sheet below comparing LE1605 (SAE110) on the top line, and Amsoil 75w140 on the second line. The LE was run for 2 seasons, the Amsoil was run for one season, I typically change the fluid once per year.

 

Lots of grey paste on the magnet both times I've drained it! I put in amsoil 75w90 because I had it. I'll def put amsoil 75w110 in next time and depending on the condition of the 75w90 maybe run 110 all the time.

 

I run Amsoil Severe Gear 75-110 in my 03S and run 75-140 in my 02Z.

I change the diff & trans fluids every year or 10k miles.

\rlr
Carolina

 

Amsoil here as well. 75-110, the guy said 75-90 was recommended. But most of us here prefer 75110

 

Was using Amsoil 75W140;switched to LE1605 this year.
Will see.

 

I just put in amsoil 75-110 last weekend as well, so far so good