P0755 Dodge -

Question

I replaced the engine in my 2004 dodge Durango after the install I took it for a test drive. It started out sluggish and the check engine light came on and wouldn't shift out of 3rd gear. When I checked the codes it came up with a po 755 which is the b shift solenoid the trans worked fine before I have checked for missing grounds loose plugs and anything else I could think of,is there any way I can test the solenoid to see if its bad or is there anything else I can check it is a 5.7 hemi