Ok, going right back to the first post, my understanding is that you demoed a cat mulcher on the CTL ( Cat289) and it worked ok. Then you purchased a used mulcher, older but the equalivent to the hired mulcher and it won't work.
Before you end up looking like a goose check out the mulcher. Check the casedrain flow to find out it the motor has worn internals( scratched lens plate, worn rotating group are things most common). Check motor manufractures spec's. Most info is online.It should have a control box with counterbalance valve, pressure relief valve, loop flushing valve and a break valve all of which have a heap of O rings that bake hard and can leak causing oil to bipass.To test this pressure test the carrier then at the outlet of the control box. The reading from the control box should be 10% lower than the carrier,any more than that is where the problem is.
Hope this helps