If you can swing it, get an OEM service manual. There are several on ebay at the moment. A little pricey, but once you get one, you'll not be sorry. There are brand new reprints on there for $132.00 that look pretty nice, with binder an all. If you open that ad, and scroll down, you can see how well they are illustrated, and have step by step instructions, along with actual pictures of the machine, not a lithograph.
The diff lock on mine was frozen up going through the housing. Took it off, and soaked with penetrate, then gave it a good dose of never seize.
No real trick to replacing the seals, other than getting the screws out that hold the bull pinion shaft bearing and seal cage. They are a large Phillips head, counter sunk screw. They are only torqued to 15 in. lbs.. I used one of the hand impact drivers with bits to get broke loose. I replaced them with the hex drive type. I'm pretty sure they are a 3/8" screw. Much easier to re-install to the torque setting, and not having the bit cam out in the Phillips head, even though it was only 15 in. lbs.
That, and getting the bearing/seal cage back over the bull pinion shaft, without inverting the seal, when sliding it back in, over the splined shaft. The manual calls for using a thin shim stock to wrap around the shaft to do this. I posed this question on a forum back in 2010 when doing the brakes on my 310B. A retired heavy equipment mechanic told me to clean the shaft well with solvent, then starting just to the inside edge of the shaft where the splines end, and the smooth part where the seal rides, wrap with electrical tape. wrap the tape to the outside end leaving a pig tail, then coat with oil. Slip the cage over it, being careful not to invert that lip. When it is in place, and secured, get hold of the pig tail, and pull the tape off. It will unfurl slick as a button.
Also only do one side at a time, or it will let some internals drop.
Mine has the full cab ROPS, with no glass. They made a kit with vinyl borders, and plastic windows that snapped on for a seasonal cab. To make it easier to access the brake chamber on the right side, I removed the fender. Cab was held up by a chain hoist on a beam in my shop. Sure made it a lot easier to work on.
No need to find a parts manual, as Case Construction has one online:
Official Case Construction Equipment Online Parts Store and Parts Look Up. Parts for Case Equipment and Construction Equipment. Parts Store for Case Wheel Loaders, Case Excavators, Case Skid Steers, Case Original Parts. I've already got it to the 480C manual, just select which function group you want to look at. Great to look at if you don't have the service manual handy, and want to see what the internals of something looks like. And, if you select a dealer, it will give the part cost at the dealer. Also, if you want to shop for aftermarket parts, you can copy and paste the part number to a search engine, and shop online, and compare prices. And as mentioned above, some parts are used on Ag. tractors, and parts are 10% less going through an Ag. dealer.