Diamond Drive Service

SnowTest November 2, 2005 3
***After reading this article, be sure to read Diamond Drive Service CAUTION*** With an increasing number of Arctic Cats now fitted with the radically-different...

***After reading this article, be sure to read Diamond Drive Service CAUTION***

With an increasing number of Arctic Cats now fitted with the radically-different Diamond Drive gearbox, the number of questions and curiosity surrounding these units is increasing.

First off, about the only service the units should require is to drain and replace the lube in the gearbox. This should be done, at a minimum, annually (once a year). When performing this service, we want to carefully measure the amount of fluid that is drained and to inspect the fluid so we can determine if there is moisture entering the case. Ideally there should only be three ounces of lube in the case; some units could have slightly more, but anything over four ounces can cause problems.

You can get the lube right from an Arctic Cat dealer, or better yet you can get an entire kit from the designers of the Diamond Drive system, Black Diamond. Their lube kit, that includes a precise amount of higher-quality synthetic lube than what Cat uses, along with a new o-ring for the drain plug and a tube of gearbox sealant so you can remove the cover and perform a full inspection. (Do NOT use chaincase lube or you will pay dearly for that mistake!)

If all you want to do is replace the lube, you can do that, too. Flip the machine up on it’s right side and you will find a drain plug on the lower rear of the gearbox behind the drive shaft up inside of the tunnel (on the first year ZR 900s it’s down under the secondary clutch on the other side of the gearbox). Have something ready to catch the lube (a measuring device like a Ratio-Rite works good) and remove the drain plug. Once all of the lube has drained (it is slow to drain, as the gearbox is vented through the airspace around some of the threads) you will want to measure the oil once it is done draining as this will indicate if we are losing fluid through a leak (this happened to one of our 2006 Crossfire 700s).

We’ve heard a number of units may have seals that were installed backwards during assembly at the factory. This can allow water to enter the gearbox, and can lead to problems like what we experienced on our 2005 F6 this past season – “freezing” of the gearbox when it gets cold. It could also lead to excessive pressure in the gearbox, causing a “hydro lock” and, of course, rust. If the lube has a yellow appearance to it, there very likely is water entering the gearbox.

Once the lube is completely drained, place the sled on it’s left side. Here is where the trick starts – you will have to put a hose on the bottle if it is not equipped with one, and direct it into the hole. Don’t spill any, if you do, determine how much you spilled and only add that much. Do NOT overfill the case, this will cause big problems! Replace the plug and you’re done.

We’ve also heard a small number of units slipped out of the factory with zero lube in the gearboxes. If you got one of these, you wouldn’t have made it more than a couple of miles and the gearbox would have failed. But if you picked up a 2005 unit and haven’t used it yet, it would be wise to verify there is actually fluid in there before blasting off on your first ride, only to be seriously disappointed. Granted, not many units got out with this condition, but strange things happen when we’re talking about mass production on an assembly line.

You can also upgrade many of the secondary clutch components with higher quality, better fitting and more secure components from the aftermarket. Both of the threaded plastic adjusters that fit into the secondary can be replaced with billet pieces that will not move or break like the plastic pieces, providing more security to the belt fit. Realize the outer piece has left-hand threads on some 2005 and all 2006s, while the older units had right-hand threads (less secure due to the direction of rotation of the clutch).

Special thanks go to Black Magic Racing and Black Diamond for their assistance in preparing this article.

***After reading this article, be sure to read Diamond Drive Service CAUTION***


    January 1, 2009 #1 Author

    Venting detail correction to article:
    The gear box is vented to atmosphere via a drilled bolt which holds the driven clutch sheave down. Drain time is due to size of drain hole and viscosity of the fluid.
    Second item: AC recalled mountain sleds to have a stiffener installed inside the drive shaft to stop the drive shaft holding bolt (the long one) from failing. They did not do this for the F series sleds, so I would highly recommend you do this to your sled asap. I replaced all bearings and seals in diamond drive when doing this (about $550.00 cdn in parts).
    Nontheless, now that I have taken the diamond rive completely apart and become “one with the sled” I am quite impressed with the design and manufacture from a mechanical engineering standpoint.

  • roger smith

    March 1, 2009 #2 Author

    2004 zr 900 efi snow pro with 2300 miles on sled second season on sled since bought new.i drained and flushed last year with genuine artic cat fluids. had to cut last ride short do to whine(diamond drive)and terrible burnt oil smell from drive system and brake fluid level drop.track turns freely yet. any upgrades for this unit would be greatly appreciated or info on parts or high performance durability needed for this please email

  • steve frye

    March 28, 2009 #3 Author

    I have a 2004 ZR 900 EFI Sno Pro with and 3200 miles on it and my (Diamond Drive) just failed.
    While purchasing the parts to repair I was told that the drive shaft and gear ring needed were
    updated parts (changed in some way) but when I recieved the parts they are exactly the same as the ones I just removed.
    Can anyone tell me the difference between the stock drive on my machine and the so called updated version.

Your email address will not be published. Required fields are marked *