I own a ryobi 775r trimmer and my driveshaft broke inside the female coupler that connects the boom drive shaft to the attachment drive shaft. I looked on the mtd site and some other replacement parts sites and can not find the replacement part on the schematics.It is offered in the complete upper boom assmble though.Did ryobi discontinue this part so you are forced to buy the complete upper boom assembly?
Its not usually for the upper shaft to come as an assembly only. Other brands are the same way. the shaft may not been available as a single part from day one.