Metal cam gear failure

[RAM 445]

I had a steel cam gear failure on my 97 or 98 JD 445 at about 600 HRS. I understand there has been a lot of failures with plastic cam gears however mine must have been upgraded at the factory. When I tore it apart and checked tolerances I expected to see something stuck in the valve train however everything seemed ok. Oil seemed clean and the oil pump functioned ok. The only strange thing I noticed before tearing it apart was the entire front half of the engine looked like someone had sprayed a light mist of oil over it and it was covered with a dusting of dirt held in place by the oil. The dip stick was properly seated and all gaskets looked ok on teardown. All bolts seemed to be properly torqued. Oil level was to the proper level. I have the new parts to rebuild it however I'm trying to understand what caused the failure in the first place so it doesn't happen again. Any ideas are welcome. A photo of the gear is attached.

 

[10ford]

That sure looks like the OEM plastic gear to me.

 

[RAM 445]

Its a casting.

 

[buckshot721]

Whats the engine number? Sure does look like the same one I pulled out of my 425 before it let go.

 

[RAM 445]

I will have to get the serial # over the weekend as I'm away for a few days.

 

[Gittyup]

You sure it's not plastic? Looks like mine when it failed. The plastic kinda looks like metal. It's not "simple" plastic, but rather a composite. Kinda like the Honda mower decks. Very hard stuff. Also, as I recall the metal replacementi got didn't have that bolt on flange. It felt and looked
like it was machined from one solid piece of steel. No flange like shown in photo. Though I'm thinking it was pressed together somehow.

 

[vmurray]

Here's a youtube clip of a replacement job on 98 445 which looks just like yours above but noted as being plastic and a common problem - yes, I've heard of this many times before though no direct experience with it.

.John Deere 445 Kawasaki FD620d Plastic Cam Shaft Replacement - YouTube

States engines marked FD620D-AS01, BS01 have a plastic cam gear, check yours to see if its marked similarly.

Only other damage reported in this incident was bent push-rods. But it makes sense to do some proactive updates while you're in there (seen a few published lists floating around the net)... don't want to go back in any time soon

Hope it helps....

Good luck!!

.

 

[RAM 445]

Thanks for the video.

 

[Gittyup]

Suggest changing water pump, governor gear, and oil pump while in there. Watch the PTO seal. Mine has a slow leak around the front PTO after doing the CAM gear change out.

 

[RAM 445]

Thanks for the suggestions. The oil pump gear failed when the cam gear broke. Turns out I was wrong. I tore this thing apart right before catching a flight to Florida for a few days. When I got back last night I looked at the old cam shaft again and sure enough it was plastic. Hopefully the new steel gear will last for years.