Diamond drive bearing upgrade thread with lots of pictures

[Paul2727]

Max;

After you open your DD cover, your transfer shaft should slip out by hand. Heard of some that had small metal bits worked in, that prevented the bad bearing from slipping out of the machined pocket in the planetary basket. The owners solution was to pry out the transfer shaft with 2 screwdrivers.

After removing the snap rings, my 2011 DD output shaft (with planetary basket) came apart easy. If I tipped it over, the shaft would have fallen right out, no pulling needed. The difference is I never had a bearing detonate.

Attached are some exploded view drawings from my 2009. Same DD assembly in the 2011, but part numbers may be different.

Good Luck!

 

[maxandvin]

Thanks Paul,
I pried it apart as suggested. I was a little gentle before because everything else just disassembled once the snap rings were removed.

Thanks again!

 

[Paul2727]

Attached a directory of DD threads - that's your Christmas present! Good luck!

 

[Paul2727]

Bearings with lithium base or polyurea base factory grease and metal shields (non-contact seals) or rubber contacting seals are designed for slow speed applications, and for dirt / crap exposure on the outside. Bearings running with grease at high speed (above 2000 rpm) will run hot due to churning through packed, heavy, vicous grease. The 6203 / 5203 bearing in the DD runs up to 6000 rpm. For high-speed applications, all bearing makers recommend oil mist lubrication, not grease. I suspect that is why many owners have noticed damaged cages, blown bearing seals, and dark DD oil (from overheated rubber and overheated grease contamination - above 250 F). In any case, the grease will contaminate the properties of your DD gear oil, and the bearing seals will not allow microscopic crap to be flushed from the 5203 bearing during your annual oil changes. We don't need seals in the Diamond Drive because the 5203 bearing is operating in a clean, internal gearbox environment, full of oil mist. Synthetic gearbox oil is the same or better than any oil contained in any grease.

My mistake! The 6000 rpm I quoted in my December 29th, 2011 post #62 (above) is the max speed difference between the two lower DD shafts at 120 mph (estimated max for a short track lake runner). Those two DD shafts are separated by the 6203/4203/5203/3203 bearing. My calculation mistake was that the shafts actually turn in opposite directions! So at 90 mph, the track drive / DD output shaft turns at about 4000 rpm counterclockwise (with the 3203 outer race), and the transfer shaft (and 3203 inner race) turns at roughly engine speed, or about 8000 rpm, clockwise. So that little 6203/4203/5203/3203 bearing is spinning at 12,000 rpm! Way too fast for grease! My recommendation: Purchase your replacement bearing without seals or remove the seals and flush the factory grease! Heat is probably the main reason the original 6203 steel bearing cage lets go.

 

[shiznitt100]

2011 bearing update requires machining of the top gear shaft,when installing the new bearing the shaft must pass through the bearing and sit proud of the top side,if the shaft does not pass through the planetary gears do not mate with the sun gear nor does the cover fit on, 0.10mm was the last measurement i took before reassembly. I have a 2010 and additional 2011 to replace stil. I will get the measurements posted when i do the other sleds. Shaft was easy to grind down. If you are replacing this bearing on the 2011 take a total measurement off the old bearing WITH the spacer suptract that from the new bearing and machine that off the shaft.

 

[Pawel]

Thanks for this post! I have taken my diamond drive out of the machine and am trying to separate the planetary gears from the housing where the problem bearing is located. I cannot get these apart. What am I missing? I have a 2011, I have removed two snap rings thus far and it is driving me nuts because it will not come apart and I know it will be something simple! My drive is ruined, metal everywhere and more than one wrecked bearing. GRRRRR

Thanks in advance

Im having the same frickin issue, tried using a pry bar on it gently but no go! Did your screw drive do the trick?

 

[robert123]

Wonderful post it is. Thanks for sharing the details. Can you please tell me how effective single point diamond machining is?
____________________
diamond machining

 

[Link11efr]

I have done this mod on a 2009 500 with the mechanical reverse and it seems the reverse lever will not engage with the bigger bearing. Does anyone know if this is normal, if so no big deal, rather have a working sled then have reverse. 5203 bearing would grenade after 50-100 miles.

 

[CatMan16]

Ttt for easy reference

 

[IGBT]

Just a little update. I just took apart my 2011 SnoPro M8 diamond drive that I upgraded last year to a double row SKF3203 bearing. Everything was clean and silky smooth after about a 800 mile season. I put new oil in and put her back together, now with a little more confidence that this problem is fixed. I did have problems again getting the diamond drive off the studs but I figured out a simple solution. I went to the hardware store and got a 3 inch grade 8 bolt 7/16" 14TPI. I threaded this in where the shorter axle bolt normally is and it allows you to knock the drive off the studs without bottoming out the short bolt or worrying that you are munging threads because you only threaded the short bolt on a little bit. (obviously when done and re-installing the dd, use the original short axle bolt!)

 

[fj40]

Hi all I am up grading my bearing to a NSK 3203B2RSTNC3
My question is this bearing was a sealed bearing with grease in it.
I took off the seals and removed the grease.
Now it looks like the cage holding the ball bearing in place is made of a plastic not metal.
So is this ok or should I get a different bearing

 

[Stg2Suby]

I'd use it. The overall bearing design is far superior to what's in there now even with a plastic vs metal cage.

 

[Paul2727]

The standard SKF 3203 bearing "SKF Explorer 3203 ATN9/C3" also has a nylon cage (glass-fiber reinforced polyamide 6,6). A nylon cage is actually the best, least friction, highest rpm, etc. Better in every respect in a DD, as compared to a steel cage.

Merry Christmas!

 

[meierjn]

Great thread as well!

 

[SKDeuce]

Pulled mine out of my 2010 last night. It has 1725 miles on it and everything is perfect in there. Think I am going to change the bearing out anyway since my brothers just blew a couple weeks ago and it's apart already. I have probably read every forum about the topic and it's about 50/50 on whether the shaft needs to be machined down a bit. Should I just take it and the new bearing to a machine shop and get them to match it? What am I looking for as far as how it sits on the shaft compared to the narrower one?


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[Paul2727]

SKD: My recommendations:

1) Remove your DD from your sled.

2) Disassemble your DD cover & transfer shaft.

3) Remove your original Arctic Cat transfer shaft bearing & spacer.

4) Press your new 3203 bearing onto your transfer shaft.

5) Reassemble your DD on your work bench (not in your sled).

6) Check: Without forcing it, will your DD cover close? Based on those results do either A) or B).

A) If your cover won't close, measure the cover gap using feeler gauges. My 2009 M8 cover gap was 0.016". Make plans to remove the new bearing and machine your DD transfer shaft. Use the cover gap measurement + 0.015" for DD output shaft axial free play (for thermal expansion).

B) If your DD cover closes easily and completely, bolt the cover onto your DD and check your DD output shaft axial free play. My 2011 HCR free play was 0.012" with my 3203 bearing installed. Therefore, no DD machining was required. (Different problem: My HCR track drive shaft was too long and required machining. I know your track drive shaft isn't too long, because your original DD transfer shaft bearing survived. Mine was gone in 300 miles.)

7) Seems every machine is different, even same year, and the same model. Only way to know for sure is to measure.

Good Luck!