I was driving my '97 5-speed yesterday and it popped out of first gear twice during one day. I have experienced it pop out of first before, on separate occasions. Yesterday, it came out of gear once at very light throttle, and then under heavy throttle as I was starting on a hill (loud POP). I have only owned the truck for 1,000 miles and it has a total of 263,000 miles on it. My questions...

Would a tranny fluid change help keep this situation to minimum, or even make it worse? Is there any special maintenance that can keep this from becoming a constant problem? Or, is it inevitable that once it starts popping out of gear, it only gets worse from there (like a clutch starting to slip)?

Thanks.

I had similar problems. It would pop out of first gear when not fully engaged.

I replaced the manual transmission fluid (used amsoil, others swear by redline) and replaced the shift lever bushing with one from marlin crawler. Much improved, but it still happens occasionally when I am lazy and don't get the shift lever all the way into first.

Try replacing the shifter seat.
It's a rubber bushing that hardens a cracks over time.

Look here

Thanks.

SoMany, are you talking about a bushing like the one fourwd linked me to? For that price, I'll definitely give it a try. I need to order the oil to replace first.

I have replaced the shifter seat but it did not help my situation. Now my First gear is always popping out and hard to get moving. Has anyone had similar issues and solutions?

Its a 2000 SR5

Yeah I have had that happen. With a "beat" 5 speed, you have to make a more concerted effort to make sure you fully push all the way into 1st. If you do a lazy shift you may not fully lock it in and it can pop out. I had a 300K 5 speed that would do that, was also loosing its syncro, would get grinding on normal shifting occasionally going from 1st to 2nd. So my gears were getting beat. I ended up finding a cheap low mileage 5 speed for $250, had it torn down and rebuilt regardless, in hindsight I should have just installed as is, but I wasn't sure about the "low mileage". You can put in new gear lube, may help a bit. But keep your eyes out for a good replacement low mileage transmission, or expect a rebuild, aprox $1K not not including remove and install, but good if you can do your own install. In the mean time, use extra effort and make sure you're fully engaged all the way into 1st.

could also be the shift forks, internal, which I have seem when people like to ride and hold the shifter, then it starts popping out of gear and they hold it more into gear, wearing the shift forks faster.

I would try the easier cheaper fixes listed above first

Mine does that occasionally. However, it only does it if I don't fully engage the first gear. Also, it only does it when I start moving but never while moving. It is annoying but I don't see it as a huge problem.

The items I call fulcrum pins in the transmission tower may be loose and this might cause a problem in which a given gear is not fully engaged. I wrote this up once before, with a picture, so it'll be clear what I'm writing about.

https://www.toyota-4runner.org/1915180-post19.html

At any rate, it's easy to check.