Well, shucks. ask the service manager at the (yellow) JD dealer. You can do it when you ask for the complete history on your JD - if they do that there. He can show you where the "engine computer" mounts to the inside of the frame just forward of the battery box after you open the hood. Or hopefully in yours it is in the cab, instead. It's a box not much bigger than your hand and has a 20+ pin plug in one end. I bet he knows all about it. My dealer had two rebuilt units in stock for instant trade-out. They have to be matched to the tractor....
BTW, everyone at my yellow JD dealer is a delight to talk to after the green JD dealer.
They didn't sell me the machine, never met me, and they are huge dealer. But everyone there always tries to see if they can add a little extra value to my visits.
Yeah, the 310 is a classic. Each model is better than the last. Good ones are amazing durable.
On the other hand, you need to buy one with everything you want. Just adding a thumb to our 310 would cost about half what the Kubota cost new - and the Kubota came with a thumb.
rScotty