Tractor is an AC 5040. New to me. Runs great, previous operator said everything was working fine except minor things like lights, instrument panel. Fired right up and took her for a spin. Lowered the 3-pt with a bush hog attached and did some mowing. Went to lift back into transport position and nothing. No lift. Checked fluid and seems fine. Took off control lever housing and that's as far as I got. What do I need to check next? I'm new to older tractors, and have the operator's manual but it does not explain any troubleshooting. Remote line has pressure. All help appreciated. Thanks.