I have an 08 king quad 400. I can find what oils to use in the engine and diffs.

 

I've always had good results with Shell Rotella T6 5w40 in my Arctic Cats. The Cat 400 and 500's were Suzuki motors. Full synthetic and wet clutch safe. Don't know how Suzuki sets up the 400's, but AC had the rev limiter set at 8,500 rpms. I figured a good synthetic can't hurt. Blackstone Labs confirmed, I got 50% less wear metals than with Mobil 1 Euro formula and 25% approx , running conventional Motorcycle 10 w 40 mineral oil. 500 mile changes.

 

I would seriously second the synthetic oil in engine and in the diffs. The Shell Rotella is a good one, I will be going to that oil on the next change. As far as the diffs are concerned why not go with synthetic there also, keep in mind that syn lubes are actually thinner than equivalent dino oils thus they use less fuel but they also protect better for only a few dollars more. I use the 75-140 weight diff lube in my machine in full synthetic as it is no heavier than 80-90 dino lube but it protects so much better. Checked with the manufacturer about the 75-140 vs the recommended 80-90 and they said if it was syn lube then it was good to go !!

 

Don't use synthetic, it will ruin your clutches. This coming from an old gearhead. Use the old school regular **** and happy trails brother.

 

Synthetic is best imo.

 

Well, I had 9,000 miles on my AC 500 when I sold it, mostly ran synthetic, and T6 for several years. The new owner has been using T6. I drove it the other day and it's nearly as fast as my new AC 700. I'll continue to run it in all my Cats. T6 is a full synthetic with excellent anti wear additives, for diesel motors. Works great in gas motors. Has no "friction modifiers" that mess up a wet clutch. BTW, a lot of conventional oils have friction modifiers. I works great in supercharged Chrysler hemis, too.

 

Rotella T6. Ran it in my old Honda for years and never a problem. Same for my sons SV650 and SV1000 Suzukis. No clutch slippage at all as it doesn't have friction modifiers that a lot of car oil has.