Got a pretty loud cluck coming from maybe the transmission (but not sure) on acceleration and deceleration. Only clunks once while accelerating hard and as soon as I hear it I let off and it clunks again on the deceleration. Keep in mine this atv has a turbo and seems the clunk happens about the time I build some boost and put strain on the driveline. Thinking maybe silent chain in the transmission but wanted to get your guys opinions before tearing it down.


F.A.S.T Racing

POLARIS 800,STAGE II TURBO,CHEMICALLY INTERCOOLED,DYNOTUNE NITROUS SYSTEM,40MM CARB,TANGELO ORANGE PEARL PAINT,CUSTOM RACE CUT PLASTIC,DIRTY DAWG CLUTCHING,CUSTOM MUZZY EXHAUST,SCRAMBLER BUMPER,28" MEGA MAYHEM,NERF BARS,OIL & TEMP GAUGES,K&N FILTER,3"WHEEL SPACERS,HEADLIGHT & REVERSE MOD,2" RD LIFT,1" FORWARD A-ARMS

 

The Polaris "clunk" is usually drive line components. Check the u joints first but the yoke splines fit loosely when new and a little age/wear makes it even more noticeable on acceleration and deceleration.

 

It's always had the polaris clunk from day one when I bought it new. It put in all new u joints from front to back less than 100 miles ago. Spline yoke has also been loose from day one. This is a hard cluck while accelerating around 35mph or faster when building boost and putting a strain on the drive line. I have the transmission out. I will report back with what I find in a couple days when I have time to tear it down.

 

In that case it may be something deeper then.

 

Didn't find any reason for a loud pop in the transmission. I did find a bad bearing and the silent chain to be loose. Here's some video's below. Think maybe the 4wd might be trying to kick in causing the pop but still don't know.

 

I'd be willing to bet that chain is most of the source of the clunk that's a lot of slop I would definitely replace /bearing too! It looks similar to the trans in my atp 500
Keep us posted as to the possible cure

 

I hope that is what the clunk is from. The chain touches the case on each side if I move it over with my finger. I don't see any marks on the case but it can't be far off from rubbing it. I will report back if the chain fixes it.

 

Got the silent chain today and man what a difference. Its alot tighter. Still waiting on the bearing to get here.

 

Yah that puppy looked stretched wasn't going to get better! how many miles on atv? I gotta watch mine.A post from mechanic on this forum said to make sure you use Polaris AGL transmission fluid [thin]in those trans says reg gear fluid is to thick and wont make its way up to top transmission bearings FYI? Hope its all it was

 

Around 3000 miles. I use synthetic transmission fluid but the transmission was run dry before. The grey sealer Polaris used to put the cases together was to thin and leaked all the fluid out. That's when the bearing went out as it started making a noise and that's how I found the transmission was dry. Filled it up with fluid and the noise mostly went away. I really hope this fixed my problem. I got some trails to hit.