I have a 92 pickup v6, manual 5 speed. I'm having a hard time getting the truck to go into gear. When I put pressure on the stick to push it into 1st it feels as if there is resistance, and I have to put enough force on the shifter to break through this resistance. Going into second it will grind before meshing and actually engaging the gear even when my foot is to the floor, also in second when it is in gear and I'm cruising along and hit a bump, it will bounce the truck out of gear, I have to reclutch and place it back into second to continue. Third, fourth, and fifth are all fine and smooth. When the truck warms up it seems to shift a little better, but still has resistance against first and second, it's just not quite as bad. Any ideas on what this is? I heard something about changing fluids but I'm not sure if that works for this truck. Thanks guys!

 

Your clutch is not releasing. After you check the clutch fluid level, consider this:
https://www.yotatech.com/forums/f116...fatigue-32667/

 

If you havent already, I'd recommend replacing the shifter seat and socket. That'll definitely help with the popping out of gear issue.
I replaced mine when I first got my truck. Shifter was pretty sloppy and loose. After replacing the socket and seat the shifter is way tighter but now the gears clash a little bit in 1st and 2nd and going into first from a neutral.

 

If I am not mistaken, it is pretty common for there to be resistance on older manual transmissions. The synchros that let you shift into gear smoothly while driving wear out over time, causing it to become harder to shift smoothly, or even create some grinding. I believe 1st and 2nd would be more warn because you shift in and out of those gears more often over the life of the transmission, therefor causing more wear on them. If that is the case it would probably be best to just live with it, I am not sure however about your issue with it popping out of gear. It is also common with worn out synchros for it to shift smoother once its warmed up. How many miles are on the truck? I bet if it is high mileage it is just warn out synchros.