644b Deere Loader Low Trans Pressure Question/Issue

A little background info: I have a 644b Loader with around 11,000 hours. The trans is a Allison tt2000 or tt2200 I cant remember. The Loader has had about everything rebuilt except the trans.

Today I went to check out the loader as the winter snow season contract is over in 3 days and started it up. Everything checked out well except that my trans pressure gauge is in the red and showing me only 125 psi or so. I moved the loader around in forward and reverse and it did not hesitate or lack any power. About 3 days ago we had a inch or so of snow and the guys ran the machine for about 5 hours with no issues. The guage on there now is older but a mechanical gauge. With this scenario I have a few questions. I ordered a set of gauges to check trans pressures at a few points and will do that in the next few days. The gauge will also let me know if just the mechanical gauge is off or if there is actually low trans pressure. I know there is a bunch of things I need to look before assuming its the trans has a internal issue but can I run this machine without causing alot of damage if it is actually low on pressue or will doing so really grenade the rest of the transmission?

Feel free to repond to this post with any tips or sugesstions. My email is theo1035@comcast.net and cell is 847 668 9734 as well

Thanks!

How long since filters were changed? What type transfluid are you using? And of course how is the level. My 644b @ idle shows little pressure but comes up at operating speed to I'm sure on my gage is 125#. It's 40 mi away so can't check it right now. A gallon low afects how mine operates. I have some steering leaks that I have'nt got around to fixing.