I have a1952 Olds with 4 speed hydramatic, just recently the trans has developed a problem where it wont shift out of first for the first mile, then once pressure has built up it will shift whough all gears normally. Any ideas what is causing this I dont think its adjustment, probably more like something sticking. Does it need a rebuild or is it something i can fix without too much bother.

 

It could be a sticky 1-2 shift valve (in valve body) or the G-1 portion of the governor is sticking. Since you say it shifts ok after awhile, I would take it that the TV rod is adjusted correctly.

The valve body and governor are removable without transmission removal. Valve body requires side cover removal, as does the governor. Removal of these items are described in Motors Manuals of that year range.