Hi there.
This is completely unrelated to A bodies or Mopars in general. I came across a post where you mentioned having worked for Hyster Forklifts. Ironically I own one and use it frequently in my shop.
I've been having trouble with it being underpowered. For instance, it struggles going up minor inclines even without any load. Hydraulics work fine, in fact that's how I found your post under 'Oil Pressure Fluctuation' where you mentioned the hydraulic relief valves could get clogged.
If you have any idea on what could be the issue, it would be greatly appreciated. I was thinking it could be the transmission, perhaps low fluid or something of that nature. It's a Hyster 40.
Thanks- Adrian