Sauer danfoss 40 series m46 tandem drive pump

Danfoss m46 tandem hydrostatic drive pump off a 96 case 1845c. New oring kit swash plate rotating groups. The charge pressure is fine but I had a guy tell me there are othe parts in there that get wore out that would let fluid bypass. The problem I'm running into is when you engage into a load the tires don't spin out and the engine rpms don't die down it just runs as if nothing happened. Also I was looking at psi checks and it says on the top of that pump there are 4 ports and they are...

Sauer danfoss 40 series m46 tandem drive pump

Sauer danfoss 40 series m46 tandem drive pump