Howdy!
1990 should be a dash 1 machine.
Are you referring to the 3 green LEDs below the hour meter? Left is auto-idle on, centre is turtle travel speed, right is rabbit travel speed.
Does the machine mistrack on level ground? Could be anything from track tension too tight, siezed rollers, binding final drive, propel brake not releasing fully, worn propel motor or leaking counter balance valves, leaking rotary manifold, pilot issues etc. Need more info to even guess
I've never worked on a 150, Does this machine only have one pump like a 120?
As far as the pump whine, is your oil foaming? Check for suction leaks, there is a mesh suction screen inside the tank, you can access it through the tank fill cover, I recommend draining the tank before removing the screen as any debris down there will go directly into the suction piping. Have you changed the return filter? If not or you have the old one, cut it open and look for brass, it could be from your pump or the lazy travel motor. I'm guessing your pump is just getting long in the tooth.
Is it gear oil leaking from the swing bearing or hyd oil? If gear oil it's the swing drive pinion seal, no special tools required, the seal slips over the pinion gear. On my 790D same as dash 1 EX220 the snap ring on the pinion gear broke and took out the seal, If the pinion bearing is loose and causing the seal to leak it will require a 50ton press to re&re the bearing.
Hope some of this helps!
Greg
