Thanks, I'll reach out to Clarendon and see if they can help with the hydraulic filter cross reference. We have the elevator adjusted, but the chain still stalls under a bit of load. Dad has run an elevating scraper in the past so he's managing the cut thickness and keeps the Detroit screaming, it's either a relief valve issue (although it stalls in forward or reverse) or we're not getting enough pressure through the control valve and it needs adjusting and/or repair. We'll get it sorted, thanks for the comments and the potential parts supplier!