Thunk in M818 when turning.

[Civilianfarmer10]

I get a thunk sound from somewhere on my M818 when turning. It can happen in any gear and in high or low. I am thinking about changing the oil in the differentials but I am open for suggestions. Thanks.

 

[jwaller]

transfer case sprag. search for lots of info on this topic.

 

[dmetalmiki]

Dont ride in my M54A2 then! (cos) when you turn/backup) on lock (or near) it give such a CLONK it could scare ya outa the cab! Only the one does it..and my fire truck every time as well. Before panicking over sprags ..check (and or) oil/lube/grease the REAR SPRING HANGERS they MOVE/SLIDE on tight turns you can see the movement if someone moves the truck for you.. sometimes if parked on lock loaded you can see the deviation, looks a bit "out of track" exessive wear on the rear torque arm bushes would also cause this?

 

[Alredneck]

I think Jwaller's onto something!

If you use your truck on the road alot, disconnect the front driveshaft ( make sure to keep it with ya incase you go offroad ) and you will be able to turn tighter.

 

[Civilianfarmer10]

I don't understand what the sprag has to do with turning?

 

[M813A1]

Consider looking at the rear upper and lower torque arm bushings they will allow excess movement of the rears !! Another things is grease the front spring shackles !! They dry-out and the springs will make noise when you turn !!

 

[Civilianfarmer10]

Thanks for all the input. I'll post if i find anything.

 

[73m819]

dropping the front drive shaft wont help in turning, dropping the rear driveshaft between the rear axles will,

 

[Alredneck]

I know for a fact droping the front does turn tight and easier. I drove a M54 on a over than4500 mile road trip dragging SS equipment around earlier this year. I will see if I can scare up some pics but the ole girl is sitting waiting on a new multi or engine swap. Can hear this pistons slapping in the cylinders. Wont start at all without ether and to keep it running hold it on the floor, and know its not a fuel issue, checked that first. Compression is the problem, lots of smoke and no power. Barely got it back to the house.

 

[Civilianfarmer10]

Well I did some poking around and I think dmetalmiki hit the nail on the head. I found the noise is comming from the leafsprings sliding around. I guess this is normal since nothing looks broke or worn. There is about 1/2 inch of space that these can shift and I can see the metal shinned up. I am also going to take M813A1l's advise and grease the front spring shackles once I find out what and where they are. I should have mentioned in my 1st thread that It only does it under load. We are pulling a 43 foot hopper bottom with 1000 bu of corn in it. Thanks again for all the great advise.

 

[jwaller]

I should have mentioned in my 1st thread

no problems. yes with weight you will hear the rear spings shifting around. without the weight you don't hear it.

make sure you also grease the rear spring pivot. it's under the conter spring mount where it attaches to the bogie. loosen the center cap when pumping grease.