2009-2011 Diamond Drive Bearing Failure

Coldfinger · Mar 9, 2012

Lets hear more about the guys running without seals, like what bearing number, machined or not, how many miles have they lasted so far and has the bearing been inspected at least visually to verify it seems to be holding up?

I've wondered all along about the seals. I've said before, seems like the bearings that have failed have not completely locked up/failed. Thinking the sealed bearing doesn't get lube like it should, then that causes the cage to fail, and the cage failing pushes out the seal which now allows oil to get into the bearings. Once oil gets to the bearings, even though the cage is messed up now, the bearing still seem to function to some degree though the lifespan is severely shortened now.

A comment on oil level - I don't know if the bearing is submerged in oil when the sled is sitting still, but once those gears are moving I'm sure the oil level drops because it is now being flung all over the inside of the DD. Now if the oil is being flung all over, it may make sense that the bearing may be situated such that it is no longer submerged and it may be isolated (pocket bearing as BDX said) from oil.??

Paul27 · Mar 11, 2012

Measured 2011 HCR Tunnel

Used bgreen776's method to measure my 2011 HCR drive shaft (see his post #327). Thanks !!

Used a dial indicator (picture 1) to measure my Diamond Drive (DD) gear case move outward 0.095" as I loosened the DD tunnel mounting bolts. After re-tightening, the dial indicator went back to zero, which proved my make-shift foundation was solid (picture 2). The measurement could be off due to dial indicator flex. Couldn't believe the tunnel moved that much, so I measured inside my tunnel using a steel bar and feeler gages (see pictures 3, 4 & 5). I cut the bar to fit exactly inside the tunnel. Then tightened the DD and used feeler gages to measure 0.105" of tunnel flex as shown in the picture. That measurement could be somewhat inaccurate because it was a few inches away from the drive shaft center line. So, I decided to average the two measurements and use 0.100".

In addition, Arctic Cat did not install the brake-side bearing shield which is 0.016" thick (P/N 2602-076, pictures 6, 10 & 11).

With a new SKF 3203 bearing installed, my DD has 0.012" of axial free play at the output shaft, as measured with a dial indicator. I want that to be fully extended, with the large DD output shaft bearing held in tension.

In addition, I allowed 0.002" for; a) measurement errors; b) tension in the drive shaft and; c) rounding off my numbers. It's better to have the drive shaft in tension, rather than compression which axially loads the 6203/4203/5203/3203 bearing.

For all those reasons, I machined 0.130" from my HCR track drive shaft (0.100" tunnel flex + 0.016" bearing shield + 0.012" DD free play + 0.002" extra).

Found my track drivers were 1/16" (0.062") closer to the DD side (offset about 1/32 or 0.031" from the tunnel center line). So the first thing was to machine 0.062" off the drive shaft brake-side shoulder to center the drivers plus allow the 0.016" added space for the bearing shield, plus the rounding amount (0.002"). With that, the first 0.080" had to come off the brake side of my track drive shaft. The balance (0.050") was split between the two sides, or 0.025" each.

Picture #8 shows 0.025" machined from the DD end of my drive shaft, and picture #9 shows 0.105" (0.080" + 0.025") machined from the drive shaft brake-side bearing shoulder. This proved to be less than what was needed. After reassembly, I have 0.015" outward tunnel flex, or about 1/8 of what it used to be. Maybe it will "settle in" after some run time - I'll check it at the end of the season. Since the BDX 5203 bearing survived for 700 miles with 100 thou of axial pressure, my new SKF 3203 bearing will probably survive 5000 miles with only 15 thou of axial pressure from tunnel flex. Good enough! Job done!

History of the sled: At 300 miles the stock A/C DD 6203 bearing in my HCR was shot and replaced with a BDX 5203 by the previous owner, with no DD transfer shaft or drive shaft modifications. Now the machine has about 1000 miles and amazingly the BDX bearing was in fairly good shape (see picture #7), only loose 0.001" in the axial direction. The grease was gone (boiled away, with signs of high heat on the cage), but otherwise the bearing was fine - which prevented DD gear damage. The BDX (Peer) 5203 is obviously a much stronger bearing than the stock Arctic Cat 6203 because the 5203 endured 700 miles under high axial load, when the 6203 could not handle 300 miles. I replaced the BDX 5203 with an unsealed SKF 3203 ATN9/C3 with zero axial clearance. With the new SKF bearing installed, which is 0.002" wider than the BDX, the DD cover closed as it should, and the DD output shaft had 0.012" axial free play. So there is no axial load on my new 3203 bearing due to the DD, and my DD transfer shaft did not require any trimming. My entire problem was my too-tight tunnel and/or too-long track drive shaft.

Good luck to M8 and HCR owners !! Hope this helps with your measurements, decisions and repairs.

GREENBIRD · Jun 2, 2012

09 crossfire dd

ok i done with machining the transfer shaft and drive shaft on a 09 600 crossfire and all back together and i when look for some torque specs in in the service manual i notice that they want the gap on the large snap/retaining ring
positioned in certain spot is this necessary or do i just need to make sure it is
properly seated

␣NOTE: Make sure the gap of the retaining ring is properly positioned as noted during disassem- bling.
MS518A

Paul27 · Dec 25, 2012

Viper3 · Jan 15, 2013

XFIRE800 said:
no, it is needed on 09's with engine reverse because they dont have a reverse diamond drive. the 07-08 sleds had mechanical reverse which ran through the reverse diamond drive.

have a 2008 m8 snopro, was wondering if there was any DD bearing failures in this model year?

insomniac62 · Sep 14, 2013

Wanted to add my experience....

2011 tm8
1500 miles

Pulled dd, bearing was PERFECT, changed anyways to 5203.

New bearing was .060 wider than old bearing and spacer

Put a new seal on, buttoned it up, added oil,
End of story.

Stack · Nov 8, 2013

Volvokvaloya · Nov 9, 2013

Anyone here who has an opinion on the 07-09 DD with electromechanical reverse ability to transfer power..such as a M1000 Turbo with 300hp?
We all know the faults with the bearings ..but when we have fixed the bearings is there anything wrong with the whole transmission design to transfer big hp?

bullcanyon · Dec 23, 2013

Just bought an 09 m8 with 992 miles. Pulled the bearing after reading all the horror stories. Not willing to gamble with it. Bearing looked good on the outside with both seals intact. I pulled the seals and all grease had been washed out and the bearing was full of oil. Actually enough to soak through a blue shop towel onto the bench. Plenty of oil to lube the bearing. I'm putting a 3203 in there when it shows up. Hopefully it will slap together nicely.

Paul27 · Dec 29, 2013

backcountryislife · Jan 4, 2014

Paul27 said:
Won't read www.arcticchat.com. They delete forums with helpful, factual information.

Huh? I'm the mod of the m and crossfire sections... and I don't delete ANYTHING. So let me guess... you got into a pissin match somewhere else on the forum and pissed off one of the mods who actually worries about the stupid stuff... and by that you decided that I just go around deleting useful info?

Yeah... no.

Sent from my SPH-L900 using Tapatalk

Paul27 · Jan 6, 2014

backcountryislife said:
Huh? I'm the mod of the m and crossfire sections... and I don't delete ANYTHING. So let me guess... you got into a pissin match somewhere else on the forum and pissed off one of the mods who actually worries about the stupid stuff... and by that you decided that I just go around deleting useful info?

Yeah... no.

back: Do you have anything helpful, that you care to share? Your guess, your false accusations, and your insults in this thread are not correct. Three more reasons not to read arcticchat, and also good reasons not to read your posts on Snowest.

What arcticchat did a few years ago, that I found disrespectful to Arctic Cat owners, involved deleting (I don't know which moderators) entire threads about diamond drive problems, with no justification (no "pissin match", and no inaccurate or unjustified complaints about AC).

I posted repair methods, to help other Arctic Cat owners, only to find weeks later the entire thread was gone. Why bother posting if they delete good and valuable information from owners?

backcountryislife · Jan 6, 2014

Paul27 said:
back: Do you have anything helpful, that you care to share? Your guess, your false accusations, and your insults in this thread are not correct. Three more reasons not to read arcticchat, and also good reasons not to read your posts on Snowest.

What arcticchat did a few years ago, that I found disrespectful to Arctic Cat owners, involved deleting (I don't know which moderators) entire threads about diamond drive problems, with no justification (no "pissin match", and no inaccurate or unjustified complaints about AC).

I posted repair methods, to help other Arctic Cat owners, only to find weeks later the entire thread was gone. Why bother posting if they delete good and valuable information from owners?

As most with common sense could guess, they don't just go deleting useful threads for SH**s & giggles (especially in my section where most of them don't seem to venture much). While I don't agree with some of the other mods on there, I have yet to see them do this kind of thing for no reason.

There are a bunch of threads on the DD issues on there as well, silverram323 who posts on here as well posted one of them that has probably 10+ pages of comments... they've been there for years, someone just reposted in one of them recently.

Either way, sorry for your loss, carry on.

Carbon77 · Jan 16, 2014

Just wanted to share my Story on my "new" 2010 M8. 2100 Miles

Leaned sled over took bolts out for cover, the cover did NOT want to come off, attached 2ndary bolt and hit it with a slide hammer (or claw of a hammer pulling) and it eventually wiggled off but tore the gasket to pieces as it was dried out.

Had 5203 and it was in perfect condition to my surprise. Used bearing puller to pull 5203 off, pressed on the 6203, got new gasket from dealer and put back together, done and done.

Coldfinger · Jan 20, 2014

Airpoppoff said:
Just wanted to share my Story on my "new" 2010 M8. 2100 Miles

Leaned sled over took bolts out for cover, the cover did NOT want to come off, attached 2ndary bolt and hit it with a slide hammer (or claw of a hammer pulling) and it eventually wiggled off but tore the gasket to pieces as it was dried out.

Had 5203 and it was in perfect condition to my surprise. Used bearing puller to pull 5203 off, pressed on the 6203, got new gasket from dealer and put back together, done and done.

Was this a used sled when you bought it or did the dealer maybe install the 5203 before delivery? If the 5203 was perfect, why did you go back to the 6203?

Carbon77 · Jan 21, 2014

Coldfinger said:
Was this a used sled when you bought it or did the dealer maybe install the 5203 before delivery? If the 5203 was perfect, why did you go back to the 6203?

Did not know any maintenance history on it, already had the bearing so I replaced it.

EDIT: Upon review of my previous post I meant to say I swapped from the 6203 to the 5203.

bullcanyon · Jan 23, 2014

Put 200+ miles on the new 3203 bearing with no issues. My 09 required no machining. Fits perfect. Got it on eBay for $25 to my door. Bearing is not sealed and uses the oil in the case for lube which I think is better.

Paul27 · Jan 24, 2014

bullcanyon said:
Just bought an 09 m8 with 992 miles. Pulled the bearing after reading all the horror stories. Not willing to gamble with it. Bearing looked good on the outside with both seals intact. I pulled the seals and all grease had been washed out and the bearing was full of oil. My 09 required no machining. The 3203 fits perfect.

Bull: The fact your 2009 M8 DD, with an original 6203 bearing and spacer, made it for 992 miles without bearing damage indicates your 6203 bearing had little axial load, which means your tunnel and track drive shaft combination are a good fit, not pressing sideways into your DD. Another indication is your DD cover closed properly with the new 3203 bearing installed. Your machine should run for many thousand miles! Thanks for the information!

My 2009 M8 DD was a near-disaster after 600 miles. The 6203 bearing cage and seals were in pieces, due to axial loads imparted from the track drive shaft. Unlike yours, my machine would not go back together without forcing the DD cover. I relieved the DD transfer shaft shoulder 0.040" to make it fit (probably should have trimmed the drive shaft instead, a more proper solution, but did not know enough at the time).

Our two machines, made on the same assembly line, indicate Arctic Cat was unable to maintain proper tolerances during their welded-aluminum tunnel assembly process and / or their track drive shaft machining operations. The variance between our machines, 40 thousands, isn't much in comparison to a complicated welded aluminum structure, but it's enough to cause the DD bearing problems some of us experienced. The DD drive design works very well, when fabricated as intended.

Unfortunately, with improper tolerances, the DD drive design also focuses unintended axial loads from the strong parts of the machine onto a small little bearing that was intended only for minor radial loads, from the five balanced planetary gears. AC got very close to an excellent drive design, and were not quite able to execute the details, not during manufacture or during warranty service.

Looking at the 2012 M8, Arctic Cat seems to have quite a track record with that style of manufacturing management. An innovative and great design, that is close, but not quite right! If they could execute better, they would own the mountain-machine snowmobile world. As it is, many owner / riders suffer with the bullsh*t, and look for alternatives. Opportunity for Polaris and Ski-Doo. That's the American way! Free enterprise and survival of the fittest.

Glad to hear your story. Got me blathering on about all sorts of stuff! Breaks over! Back to work on my new shop! Got to have room to work on sleds!

line8 · Mar 4, 2014

Thanks to all on this one. Excellent info

b0hman · Sep 30, 2014

Changed the bearing on my sled today..

2011 M8 HCR

Meassured axial free play at the output shaft with stock bearing and spacer before I took it apart.. It was 0.077"

Put on the 3203 ATN C3 bearing, mounted all together with new gasket..
0.020" of axial free play at the output shaft.

I think this will work... This winter will tell!
Stock bearing was in perfect shape but only 1200 miles on the sled.

2009-2011 Diamond Drive Bearing Failure

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