I have a 1995 Ford F-150 XLT PU 5.8 L 4x4 that I'm having some trouble with. My check engine light is on, and The trucks Transmission Shifts extremely hard from 1st to 2nd gear (Auto) and from forward to rev. The check engine light and shifting problem all started about the same time. Someone suggested that it might be a Vacuum line bad or broken (Rotten) any suggestion on what to look for, or is this something I should refer to a Specialists? PLEASE any help in this Regards would be appreciated! Thanks!

RMP :)

Inspect for small black hoses that seem to start at the engine and end at the transmission. They could be dry-rotted and brittle.
If those lines are supposed to be there, they need to be intact. The engine vacuum signal that is sent to the transmission, through those vacuum hoses, tells the transmission how to conduct the next shift, up or down.
If the transmission can't shift properly, that could set a code and trigger that light.
Have this diagnosed and ask for different estimates on the repair that was recommended.
I hope this helped.