1994 Toyota Pickup Won't Shift

Hello,

I am currently having issues with My transmission not shifting. I can shift it manually by puting the shifter in 1st then second, then drive. In drive it will get into 3rd gear and usually that is it. Once in a while it will continue to shift up and I can cruise on the highway. A friend believes that it is a vacuum hose issue or kickdown issue, but my car knowledge is very limitted and the mechanic tells me that I need a new transmission. Any help would be great.

Thanks,

Tim