Help with Komatsu D20 bevel gear seal

Hi, I'm new here and looking for some guidance. A friend of mine needs to replace the bevel gear/shaft seal on a Komatsu D20A-6, and since he's not comfortable searching online, he asked me to help find answers. I'm trying to figure out how to remove that flange piece that sits between the nut and the seal—it's between parts 7 and 14 on the parts schematic. I've got some photos he sent over and I've marked the part on the diagram with an arrow. I'm not a mechanic, so I apologize if I'm asking basic questions. Hoping this gives enough info to go on. Thanks for any help.

It's pressed on, so you'll need to rig up a cross bar and porta power to press it off. I've hammered one off a Cat before, but I wouldn't suggest doing it that way.

I'll pass that along to him.

You're going to need a special press jig to get in there. It'll probably take 15 or 20 tons of pulling force to get that flange off the cross shaft.

Do you have a photo or link to the press jig? Can you make one yourself instead?

It's supposed to be pressed back on.

I haven't tackled this one myself, though there might be someone here who's done it before. From what I understand, that flange piece is going to need a heavy-duty puller or press—we're talking multi-ton capacity—to get it off.

You'll want to look for something like a gear puller or hydraulic press setup. There are different sizes and tonnages available depending on what you need. Ideally, Komatsu has documentation with the exact procedure and tonnage specs for removing and reinstalling that flange on the D20A-6, so that's worth hunting down if you can find it.

Hope you guys get it sorted and get the machine back in action.

I remember seeing a YouTube video where someone made a puller with a cross bar and a short jacking screw to do it.

Thanks for the help—I'll pass that along to him and have him look for the youtube video. I managed to find a copy of the actual repair manual and I'm going to print out the sections that matter for him. The seal's been leaking for quite a while now, but it's gotten really bad lately. He can barely run it without losing fluid, and between the cost of replacement fluid and the mess on the floor, it's become something that has to be fixed.

He should probably check the bevel gear bearings while he's in there.