For someone with a lot more knowledge and experience. Could I safely, exchange a 33 GPM pump out with a 40 GPM pump going back in. Maybe what kind of problems could I have with pressure? Thanks to anyone who might help.
The short answer is, it depends. Pumps make flow, restriction makes pressure, up to the relief valve setting, assuming we're talking fixed displacement, like a gear pump? Questions to be asked would include: 1) Is the mounting and input shaft the same? 2) Is this gear driven, driven off the front of the crank, or a PTO? 3) Will your hydraulic system handle the extra flow, is there any component that will malfunction or possibly rupture due to inability to pass the extra flow? 4) Assuming whatever drives the pump can handle the additional torque, do you have the horsepower to reach your relief pressure with the bigger pump? 5) More flow will always equal more heat, especially if you're exceeding recommended flow rates for valves, fittings, etc, so will you need an extra oil cooler? etc.... Some hydraulic spool valves, too much flow will cause the spools to bind, usually refusing to return to center, which can be downright inconvenient. Need to know more about the whole system to give a qualified answer.
33 gpm and 40 gpm are both at a certain RPM. If you drop the operating rpm then there's no difference (except #4 above).
Need pump type, fixed displacement or variable displacement, before any advice can be reliably given. Make and model of the machine might provide that information.