Sounds like the level is low. I would try adding a quart and see if it starts moving again.

Can someone anyone help me?
I have a Hyster H40XL model and or serial number #A177832512K and the problem I have is it will not move on its own power but yet everything else works fine! the fluid on the trans dipsticks is redish brown and looks like it has bubbles in it! or foam so to speak! with it running I removed the filter that is on top of valve body and nothing just small slow bubbles!on outside ring of the filter area! Any help is much thanks!