Is this a tranny or clutch issue?
 

Truck is an 1987 4x4 with the 22r and manual trans. Has about 185k.

So about two weeks ago I noticed a small whine when I was driving in third and fifth gear. Didn't think much of it and drove it normally. Two days ago I had to make a long trip. (Bout 300 miles) The noise seemed louder when I set out and got progressively louder throughout the day. Also started making the sound a little in 2ns gear. 4th was quiet. Sound was similar to the noise a catalytic converter would make as the heat shield rusted out. More a vibration than a real grind or growl. Yesterday I was hauling firewood and at one point put it in first gear and as I pushed the accelorator I heard a pretty loud pop and the truck popped out of gear. I can still put it in first fine, but it's a little trickier to slide it into gear. If I don't have it in right, it pops out. The other funny thing - the noise is almost gone now. Still accelerates and shifts fine. No slipping or anything. Apart from that little bit of noise and popping out of gear if I don't have it in first correctly, it seems perfectly normal.

Any thoughts on this? I was planning a trip to Chicago next week and was planning on taking the truck, but don't want to be left sitting somewhere. I'm new to tranny work. Would love some help in diagnosing this.

This doesn't sound clutch related. If it's not slipping, and it engages at the right point in the pedal, i.e. you're slave and master cylinders are fine, then it's not the clutch.

This is probably something in the transmission, my guess would be a countershaft bearing, based on the gears that it's whining in. To the best of my knowledge (limited) on most 'yota manual transmissions, in 4th gear, the input shaft transfers power directly to the output shaft, basically bypassing the countershaft. That *might* explain why it only does that in those gears.

How does the shifter feel? Is it really sloppy, or can you feel it go into each gear? If it's sloppy, like you can move it around in circles while it's in neutral, the shifter bushing may have come off, which can keep it from going into gear all the way, resulting in it popping out.

Also, check the gear oil, make sure the level is good and that it's not milky.

I would check the easy stuff first:
- do you have enough oil in there? (It takes 75W90, GL4/5, but GL4 is preferred)
- shift seat bushing (if you need to fill the oil, removing the shifter is easiest way IMHO)

Noise in specific gears, popping out of gear - Not a clutch issue.

Just a guess... worn synchronizers/shift hubs

It is time to make a decision put new bearings in that trans look around for a good used one . Get a rebuilt one from someone giving yours as a core.

As you can guess it could get to the point where it wont move or lock up. Not a whole lot of fun on a road trip.

While you are swapping out the trans is also a good time for a new clutch.

Good luck