ftp 6024 htdraaulic pump noist when cold

It's been some time since I last logged in but Ol' Alice has been a good girl and not given me a lot of grief. That being said, the hydraulic pump seems too be awfully noisy lately and I am concerned. She lifts and tilts like a champ after rebuilding the two tilt cylinders some time ago now, but since the weather cooled off, the pump makes a lot of noise for a few minutes after a cold start up. If the machine is kept in the shop, the noise does not seem so bad, but I am concerned. Can anyone suggest what type of pump is on her and if this noise is trapped air cavitation? Or is the pump  in it's death throes? I am using NAPA hydraulic oil that until the cylinder that was leaking badly was rebuilt and that is the only oil that I have ever used in the machine in the 20+ years that I have owned it.

I am assuming that it is a must to remove the counterweight if the pump needs to replaced or repaired - a job that is pretty intimidating to me, given the size and sheer bulk weight of the unit. Any help and suggestions are so appreciated. Thanks for reading this post and for any answers. Gary

maybe a tad low in oil ??

My FTP50 'seeps' a bit,so I topup every 2-3 months...

 Access to the pump, if the same as mine is kinda easy....

There's a 300# cast iron weight under the rad grille, Two big bolts to remove. I use a 'motorcycle lift' to slide th eweight onto, then transport. I did say three hundred pounds !! OK maybe not quite but it is heavy !

2.remove rad guard/screen...

3) there's 4 bolts hold the pump onto the engine, not too bad to remove

4) need to gently 'pry' or 'wiggle' pump to remove from 'lovejoy' rubber coupling..

5) that's as far as I needed to go, to change the %&**^^& alternator/fan belt.

obviously 2 hydraulic hoses will have to come off, bet those NEED to be off before you unbolt the pump...ooopsy...