I have a suggestion for you, especially if this plow and hitch are new to you and your 455.
The quik Hitch on the 455 uses some 90 degree fittings which are on the angle cylinder. The angle cylinder on this machine rides quite low and will get a lot of snow packed in around the angle cylinder and its lines. As the hitch is turned left and right, it packs the snow in the hitch and quickly turns into ice.
It's common for the ice to end up bending the 90 degree fittings in the hitch and causing a slow drip leak at first and it can easily become a full fluid leak and stop the hitch from angling the plow. I would suggest you do the following, since this is a common problem / issue.
1. I would keep a pair of the 90 degree fittings in your spare parts at home. Here is the illustration from the John Deere Parts book showing the quik hitch and the fittings and their part numbers, etc.
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The item number 7 is one to have on hand, as it threads into the actual cylinder and often, when the ice bends the 90 degree fitting, it can damage the threads on this "adapter fitting" and make using the 90 degree fittings a requirement.
As far as the actual 90 degree fittings, here is the screen shot from the parts book for this fitting. You can see the parts number and its replacement part number, etc. It's prior part number was M42829 and now its part number is X5CTX-S and it costs $5.64. It would be a good idea to have at least one of the number 7 fitting adapters number JD7838 and one of the fittings XCTX-5 in your toolbox. That way, when you do damage this fitting, you can easily make the repair and return to work.
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It is the elbow fitting shown as number 9 which is damaged and I don't think I have ever damaged the other fitting shown as number 8. So number 9 is the fitting I suggest you have on hand. They are not always easily located locally and often have to be purchased through the dealer, just so you are aware.
One other suggestion, is to use the Hydraulic Fluid dye, which is red, to make the fluid leaks much easier to see. If you don't use the dye, often the drips of water which fall off the hitch resemble a leak from these fittings. I can't tell you how many times I would see drips in a line from the hitch and I would get off the tractor to check only to find the drips are water from the melting snow.
But if you do use the dye, the red leaking from the damaged fittings will be very easy to see and with the parts on hand which I suggested above, a quick repair. The red dye is MT3668 and one very small jar treats the entire tractors hydraulic fluid system. All you need to do is add the dye to the hydraulic fluid reservoir in the back under the seat suspension base, where the hydro fluid dip stick is located on the threaded yellow cap under the back of the seat suspension base.
The 455 is a great plowing machine, especially with some weight on the rear weight bracket. I have used one for years and plowed a lot of driveways over the years.......Let me know if you have any other questions or need any informaton for preparing your machine for plowing snow. I am glad to help.........