Terex tb60

I purchased this 1997 terex tb60 basket case knowing the basket controls won't talk to the ground station due to water damage... It ran like garbage and it wouldn't run unless you jump the starter and bypass the anti-diesel solenoid on the carb... I replaced the main multiplexer board in the basket and that fixed my control issues. Rebuilt the starter switch and the helac basket rotator... Everything functions except here's my issue: Problem 1: (keep in mind this still uses 1997 ATF as the hydraulic fluid) When driving in high speed, the pump makes 2500psi which is in spec, when I flip to low speed to get out of a hole, it only makes 700psi so when it gets stuck and out of torque, you have to go get a machine to pull it out since it doesn't have the balls to drive in low speed. My question: does low speed on these set the pump pressure to 700psi? I wouldn't think so because when I activate low speed, you can feel the hubs pop free from something and engage what feels like another set of planetaries. Problem 2: I'm still gathering info on this, but the boom up, down, swing etc functions are slow as a snail... Even when all the way down. I'm thinking maybe my boom sensors are broken and it thinks it's 60ft in the air Does anyone have any insight on this?