Violent Intermittent Driveline BANG!!!! / Knock On Left Turns..... Any Ideas

[Badlildoggy]

Hello Gents,

Just wondering if this has happened to anyone..... I have a 2010 Avenger 750 HDI w/ Tracks and 150 hard hours, all of which were with the tracks on. The machine has been serviced and maintained religiously. Recently I have developed a serious irregular BANG on the left side while making left turns. You can really feel it in the floor. I have checked all the regular things, chain tension seems OK w/ lots of upward Cam movement available, sprockets look OK, Tracks are installed correctly w tire diameter positioning & inflation correct, All sprockets are secure to the axles with no side to side play ( except the fronts). I very recently had the tracks, tires and chains off ( a trip or two ago) to do a bearing check and they seemed OK. There seem to be no shiny spots on any chain or frame or bolts that would suggest any snagging.

I'm Kinda lost,

Any help would be appreciated, THX.

[thebuggyman1]

Take a close look at the jackshaft bearings first. If they are fine, go back through the rest of the bearings. Your problem really sounds like a loose chain jumping teeth on a sprocket, and that is not something you want to let go.

[msafi65]

The front axle chains don't have a tensioner and will hit the frame in front of the axle sprocket if getting loose. Also spray lubricant the front axles at the floating sprockets. Just did front chains on one that was very noisy when going down hill. Does this one have the grease zerk on the inboard end of the output shafts? Most 2010 Hdi didn't have greaseable inboard splines. They have been redesigned and the spline can now be lubed. The ones I've worked on made no noise until the splines at the output shaft failed. Keep looking good luck

[Rock Doctor]

Have you tried driving around without the floorboards, and observing the drive chains? Normal forward motion puts tension on the top of the chains (Except for the front chains, tension is put on the bottom of these). When you brake on one side, chain tension shifts from the top of the chains to the bottom of the chains, where your tensioners are located. If the tensioner teeth are not fully engaged on the block, or are worn, it's possible for the Tensioner to "kick out", causing a bit of a Bang.

This next part might seem basic, but I should ask.
When you said this:
Tracks are installed correctly w tire diameter positioning & inflation correct
What are the tire diameters? What are the tire pressures? How much track sag do you have below the center tires when the machine is lifted clear of the ground?
Does it do the same thing with the tracks OFF?

RD

[Badlildoggy]

Thanks a million, My ARGO received a grease zerk retro-fit early as there was a bit of a recall on the no-greasable out-put shaft issue. I think I may try to change the front 2 chains on the left side and see if it still Klunks, Process of elimination I guess..... Thanks for the direction.

[Badlildoggy]

I was hoping you would chime in RD, great thesis. I am also going to pull the tracks and go for a ride. What would it tell me if the KLUNK is gone while the tracks were off?

[chris davison]

I am not familure with your machine but am very familure with chain. When its gets worn it does not ride on the sprocket right. Under a load it will ride up the teeth until it goes over them dropping one tooth back in time that is the clunk you hear. I have had to change a worn chain many times for this problem. I wonder if you mark all the tires on one side at the bottom then run around and hear the clunking stop with all the marks at the bottom and see if they are all still in time. If you suspect a chain is worn take it off and lay it on the drive way put your foot on one end and pull out and push in the other. A brand new # 50 chain will barely elongate at all I have seen a worn 5' chain move in and out 1.5 inches at that point the pitch is 9/16" instead of 1/2" so it wont fit the sprocket worth beans.

[rodp]

I am not familure with your machine but am very familure with chain. When its gets worn it does not ride on the sprocket right. Under a load it will ride up the teeth until it goes over them dropping one tooth back in time that is the clunk you hear. I have had to change a worn chain many times for this problem. I wonder if you mark all the tires on one side at the bottom then run around and hear the clunking stop with all the marks at the bottom and see if they are all still in time. If you suspect a chain is worn take it off and lay it on the drive way put your foot on one end and pull out and push in the other. A brand new # 50 chain will barely elongate at all I have seen a worn 5' chain move in and out 1.5 inches at that point the pitch is 9/16" instead of 1/2" so it wont fit the sprocket worth beans.

Most roller chain manufactures reckon 2% maximum wear without sprocket damage. I have seen 3% quoted but I think that's pushing your luck.

[Rock Doctor]

I was thinking that if he still has lots of movement available on his tensioners, his chains should not be stretched that much.
150hrs........ on Tracks......... Maybe.

As for the tracks being on. If there is "klunking" when the tracks are on, but not when the tracks are off, I would suspect chain windeup. I was thinking that if there is a bit of "Windeup Tension" on the chains, and you brake to the left, the momentum of the machine rocks it forward a bit. That takes a bit of weight off the back 2 tires on the machine. Now, IF there were a bit of tension on the chains, this would be a perfect time for it to slip the 3rd tire a bit inside the tracks, making a bit of a "clunk".
Go easy on me, it's just a theory

Did you take your wheels off when you dropped the tracks, and checked axle bearings?

I would still be looking into this part too:
What are the tire diameters? What are the tire pressures? How much track sag do you have below the center tires when the machine is lifted clear of the ground?

RD

[ARGOJIM]

May also be the chain adjusters teeth are rounded letting them move downward, did you check for a stick or stone stuck in between the double sprockets? has anyone suggested track to tub contact or are we set on drive line?