I would think it would be fine once you flush it out good. Take the return line off and place it in a container. Have someone crank the truck, not start(unplug your ignition). As the fluid pumps out, put new fluid in; until it runs clean. That should be good.
__________________
PROJECT TRUCK: 1985 SWB C10 Silverado Black/Charcoal, 1990 V2500 Suburban, 2018 Suburban, 2005 GMC 2500HD CCSB, 2014 Toyota Camry SE, HAD.....1968 Camaro RS/SS Family owned since new; 350 3 speed

SOLD