I snapped the left side three point arm in two on a 3720 jd

[jim gerken]

It appeared to have been cracked one fourth thru previously (rusty) and snapped while pulling a box blade in a straight line. The break happened right next to the welded on channel which allows the anti sway link to attach. Inside the metal looked like coarse cast. The dealer refused warrantee, tractor is about five years old.
New arm cost 280 and is thicker looking. Part number changed.

 

[Zebrafive]

Looks like JD had issues with this arm if they changed it. Since the dealer will not warranty check your owners manual for how to take it to the next level with JD.

 

[pmsmechanic]

I've had the same issues with the three point hitch links and arms on my 4410. I bought new links the first time but when the one link broke again I just welded it together. John Deere has a whole update on the links which the customer is supposed to pay for. In the old days that would have been warranty.

When I broke my lower arm I didn't even bother the dealer. It broke right through the lift link hole. I welded it and it's been fine ever since.

 

[Deere Dude]

4 years out of warranty is a little long after a one year warranty. Just weld it.

 

[MH8675309]

What Deere Dude said +1

 

[beenthere]

And best to be real careful when pushing anything backwards, like for a blade.. that can stress the arms beyond their design when coming in contact with something immovable.

 

[MORRISONSTEEL]

Yes, I agree with the Dude. Not just out of warranty but well out of warranty (but I believe base machine is 3 years not 1). It does make sense however to not change a tractor model # every time there is a change to a machine or its components. Seems to me that every tractor maker has lots and lots of rolling changes in a given year. That's one of the reasons why a serial # is needed in many cases to identify the proper machine, changes. Doesn't mean your version should get updated for free especially when it seems that the part well outlasted the warranty range. Weld it, build one, or buy one. But the only way you can be assured that you will get warranty coverage after the warranty expires is to purchase extended warranty.