1971 Gilson MW won't move. Looks Ok

[Gilsonite]

Hi All,
Seems like there may be quite a few sharp minds in this forum. My hopes are I can get some insight as to what makes these hydrostatics work, and not work.
I have a few pictures and a short movie showing the unit running. Just doesn't want to move either forward or backwards.

 

[Muhammad]

Welcome to TBN.

 

[Briana03]

Hello & WELCOME to TBN!

I moved your thread to the Vintage Tractors Forum.

 

[Gilsonite]

That's fine. Appreciate the options. Any idea where to start as to the hydrostatic not wanting to cooperate ??
Fluid level looks new- maybe slightly low. There was a slight leak- but not a lot of pressure where one would assume the pump would act accordingly. Is there a primer necessary.? Thanks. Rj in Idaho.