This is a G-type four wing u-joint for a heavy truck. Because of it's size it's probably for a very big machine like one of those huge dump trucks used in open pit mining. These are usually sold by size and application. To know exactly what yours is I would need to know the bolt spread, outside diameter, etc. Yours appears to be about 8-1/4" so it would be about 210 mm across. As an example, the Caterpillar part number would be 9V7710 for one with that dimension, but again, I would need exact measurements to be sure. The link I've provided will help you find out what you have provided you take exact measurements and then compare the numbers to the ones shown in the size chart. There are many makers of these. Companies like Spicer, GKN, Rockwell make these just to name a few. The maker of yours is unknown.

This is a G-type four wing u-joint for a heavy truck. Because of it's size it's probably for a very big machine like one of those huge dump trucks used in open pit mining. These are usually sold by size and application. To know exactly what yours is I would need to know the bolt spread, outside diameter, etc. Yours appears to be about 8-1/4" so it would be about 210 mm across. As an example, the Caterpillar part number would be 9V7710 for one with that dimension, but again, I would need exact measurements to be sure. The link I've provided will help you find out what you have provided you take exact measurements and then compare the numbers to the ones shown in the size chart. There are many makers of these. Companies like Spicer, GKN, Rockwell make these just to name a few. The maker of yours is unknown.

References:

https://www.koto-ujoint.com/products/Type-G-4-Wings-Style/Universal-Joint-Cro...