Hi guys. I have an older 811E. I bought it used about 8 years ago and haven't used it much until recently. For various reasons, I converted it to 2S by taking out the Tekin 1900kv motor and replacing it with a tekin 4300kv motor and I rewired the two batteries to be in parallel. It makes gobs of power but the rear-end fishtails badly without steering input. I have been advised to perhaps reduce the viscoity of the oil in the center diff. In all this time, I've never even checked the oil in the diffs let alone try to tune them. So I have some questions. I don't think my 811 came with a setup sheet. It may be defalut or may not be. I tried to go on the Serpent site and find the standard or defalut setup. It looks like they call for 5000/5000/3000 CST front/center/rear but I'd like to confirm that if possible. So questions:
Is there a way to check the actual version or model of my buggy? Like is it stamped on the frame somewhere?
What is the stock diff setup?
What are you guys actually running? Our track is dry, very hard dirt that gets a layer of very fine powder.
If I start with new 5000 in the center diff and I still get fishtailing , how much lower should I go to see if lighter oil helps the fishtailing?
What is the easiest way to get the diffs out to redo the oil?

I am open to other methods to get the ample power more controllable.