I have a 2000 Ford Explorer w/ standard transmission.
Since last fall I have had problems shifting (details below) and taken it to several mechanics for an opinion. The diagnoses were evenly divided between:
it’s the transmission! You need a new transmission…
it’s the clutch! You need a new clutch…
and: it’s the clutch and the transmission! You need to replace both.
So here is the problem:
I have trouble getting the clutch into the gears, esp the first and second gear;. If I “play around” before actually moving the gear shifter into that gear (that is, if I nudge and nudge it), it will ultimately go in smoothly. Of course, that really delays my shifting up.
All gears are harder to shift into than they should be, including 5th gear. Fourth and fifth gear were the least gear to be affected.
I cannot shift down into second gear w/o it grinding, no matter how much I try to tease it into 2nd gear, though I may be able to decrease the grinding if I nudge it long enough.
When it first started it was getting worse (more and more difficult to shift) but interestingly, over the months, shifting has gotten a bit easier (or maybe I just became more skilled in teasing the gears into place) but it hasn’t gotten worse from a certain point on. However it seems to be worse when it is hot outside and easier again when it cools off.
I have no problems w/ the clutch slipping.
In August I may have to drive family around in extensive road trips and would love to get it fixed by then - but only the part that needs to get fixed 
I would so much appreciate any thoughts on this!!
Prior to hydraulic clutch master and slave cylinders these things were quite predictable with either a cable connection or a mechanical rod connection from the pedal to the clutch. I would suspect the master or the slave cylinder as being internally leaky.
I suspect the syncros in the tranny are worn. Your “playing around” while shifting is the clue. Are you aware of the art of double clutching? I won’t go into an explanation here. Just google it. It’s a lost art these days. It was a required procedure before the days of sychronized transmissions. Not many people know how to do it any more. Look it up. If it works for you, than the sychros in the tranny are worn. Not fatal, but eventually you’ll need to have the tranny rebuilt I suspect.
Double clutching is simple and has not been needed since transmissions with synchros were available since the early 1930s. I am old enough to have been aware of cars made since the 1930s and worn out synchros, in my recall, have never been an issue.
Double clutching requires a clutch pedal release while the trans is in neutral between upshifts or that and a throttle blip on downshift while in neutral to match engine/driveline speed to transmission gear speed to minimize gear clash. Since then, manual trans synchros have been extremely exempt from car trouble; are as durable as rear drive differentials or manual transmission gear boxes unless abused. Manual transmission synchros, over the years have been a minimal or even negligible source of car trouble.
Manual transmission synchros as with gears are constantly bathed in transmission lube.
I’m thinking this is BOTH at this point. The clutch might be disengaging, but not fully which is allowing the transmission to keep spinning between gears. Overtime that has caused damage to the synchro’s. The clutch could release but not fully for a couple of reasons. The mechanism to activate the clutch could be bad (misadjusted cable, or faulty hydralics). There could be bent parts in the clutch, and the pressure plate could be warped.
I think you get the clutch fixed and/or replaced as the 1st move. Since the transmission comes out of the car for the job, you might have the transmission opened up and evaluated at the same time. If the transmission is bad, a used replacement might be the cheapest way to go. Not many Explorer manual transmissions were made, so it might be a hard used part to find.
The reason you’ve been able to shift, and shift better, is you have gotten better at balancing wheel speed with motor speed when you shift. In effect, you are shifting “clutchless” or using the same technique since the clutch really isn’t releasing completely.