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Discussion Starter · #1 · (Edited)
Hi guys. I have a 2016 800 XT and have noticed some clunking from what I think is the rear diff. The prop shaft turns with a jerky motion and I noticed a bit of a left tire hop. It only happens at low speed maybe going 5 mph and when just starting.
Not sure if the problem may be transmission related.
All is well at higher speeds.
Not sure what to make of this.
Will try to post a video if I can.
Any suggestions are appreciated
Video link here:
https://www.dropbox.com/s/7u2b8tf7dkr5qnb/Video 2019-08-19, 7 30 39 PM.mov?dl=0
 

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For video, you'll need to put it on youtube or similar and then link it.


Commanders are notorious for the can am clunk. Google that. In short, when you push the throttle and the primary clutch spins, there is often a little gap between the ramps in the secondary and the secondary helix that bangs. Also, there may be a little slack in the gearbox, driveshaft and rear diff, which adds a little to the clunk. You hear it when taking off and when you're going slow over rutted or rooted terrain where the power is loading and unloading through the gearbox and driveline.


Putting a low speed engagement spring in the primary helps a little, in that power is applied at approx 1650 rpm vs 1800. But it only lessens it. It doesn't cure it. A roller secondary like the STM or one from a maverick turbo will get close to removing it but you'll have decreased engine braking.


I've learned to live with it with stock clutches and the low speed engagement spring. But I don't like it.


It may be that you're experiencing something else. But what I'm describing is something that regularly makes new owners think there is something wrong.
 

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I agree with everything sowindown says!!! I have it too. Sometimes it makes me think I'm losing a U-joint but everything is tight. You just get used to it.


Steve
 

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If you are not a new owner and this is a new noise, look closely at your rear driveshaft and halfshaft cv joints. Try to move them by hand, roll the buggy a little, try to move them again. If you are losing a u-joint and it lets go at speed, things can get ugly.
If you are a new owner and it is jerky only at low speed as you said, especially when turning, it is probably your rear diff. Mine has always done that, nothing wrong.
 

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If no metal in diff pull gearbox plug. Definitely sounds like a tooth on pinion gear . Both the diff and gearbox have a pinion gear.
 

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Ok. Forget my earlier comment. That is definitely NOT what mine does.

Steve
 
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Oh that looks bad. That’s similar but not quite as bad as when my gearbox went. Maybe Drop the driveshaft to see if in the diff or gearbox.
 

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Discussion Starter · #11 ·
I pulled both plugs and checked fluids.
No metal in either transmission or differential fluid.
Nice and clean.
Belt looked good last I checked.
Where to go next?
 

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Jack the machine up and roll the rear wheels see if you can feel anything . It won’t be as noticeable but should be able to feel something. If you feel something. Pull the rear drive shaft out and roll the wheels again . If you feel it still guessing it’s in the rear diff. If you don’t feel anything reach in and turn the output shaft on gearbox and see if you feel it . If you don’t feel it there then I would pull rear diff and separate the two halves and if it’s in the rear diff should be noticeable. Need to make sure you don’t have bad joint or joints as well before pulling the diff.
 

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Discussion Starter · #13 ·
Oh that looks bad. That’s similar but not quite as bad as when my gearbox went. Maybe Drop the driveshaft to see if in the diff or gearbox.
Back at work on this thing. I only use it in the summer when I am at the lake so picking up the project. I took the diff apart and it looks totally fine.
When you say drop the driveshaft you mean the prop shaft from tranny to rear diff?
 

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Discussion Starter · #15 ·
I have started the machine with the rear diff removed. No clunking noises but when I turn the rear driveshaft by hand it seems to turn rather roughly In the gearbox.
I am also looking at the front driveshaft and i am wondering if this is the way it should look? So much of the splines showing?
65956
1595623211186.jpeg
 

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Yes should be bolt and washer . So if bolt has come out that maybe allowing the slip yoke to compress and exposing more splines on the output shaft . It’s a loose fit save as the rear output shaft yoke but it spots it from sliding in and out on the shaft .
 
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