I've read that turning the transmission emergency valve screw all the way in helps with the issue of the pioneer 700 not shifting out of 2nd into 3rd. Will it actually improve 2nd to 3rd gear shift and after I tighten the screw do I just put the lock plate over the front of the screw and tighten it back down? Thanks
LOL...no.
The purpose of the screw is to allow a hydromechanical bypass of the electronics in case something goes wrong with them. Turning it in locks the tranny in 2nd gear, and ONLY 2nd gear, to allow you a chance to get back to help.
What is the shifting issue?
Assuming its warmed up, Usually when these don't shift right its the oil level. Check it using the procedure in the manual. You can't just randomly pull the dipstick out and check it, as it won't give the proper reading.
If the issue is with a cold machine, its just something you'll have to live with. Synthetic oil helps, but they all tend to shift funny/poorly until some heat gets in the oil.