Went to Case/IH and came up with these part numbers for an optional front pto drive pump for a 424. Shows part numbers for gas and diesel.
PUMP ASSY, front PTO driven, optional with 383513R92, gasoline engine tractors order flange & shaft, 388164R1, hub, 488161R91 & pump, 383514R92, diesel engine tractors order flange & shaft, 388166R1, hub, 488161R91 & pump, 383514R92
Product No: 378872R91
There were 4 pumps available at one time, but just shows two, as far as getting parts now. I copied and pasted the flange and shaft number to IH parts at Messicks, and it came back as a bearing retainer. Ran the one for the hub, and showed a shaft flex coupling. Price was like $308.00.
If it is an aftermarket brand loader, you may try contacting the manufacturer, or a dealer that sells them, if they are still made. Many had front mount pump kits available.