Toyota Repair: 1993 pickup pops out of gear, worn gears, clutch adjustment

Question
My 1993 four cylinder 2wheel drive standard transmission pops out of 3rd and 4th gears on deceleration. It sounds like it might be my syncro's but what else should I expect? Worn Gears?  And what type of clutch adjustment does it have? Because it won't go into gear easily when the weather gets hot.  I also have a problem with the front brake rotors warping periodically. It seems that my rear brakes don't auto-adjust properly. Wow! I sound like a nagging wife.

Answer
Although it may be a more serious problem a common problem is that the shifter bushings are worn or have disintegrated, check and replace the shifter bushings by removing the shifter from the transmission shift tower and inspect the bushings, there are two teflon bushings that are known to cause the problem, one is in the top of the shift tower, it is about 2 inches in diameter and fits inside the shifter opening the other one is at the end of the shifter, it may be a good idea to buy the new ones from the dealer first so you will know what to look for. If the shift bushings are not the problem it means that there is an internal transmission problem,this can be caused by worn shift forks or shift sleeves, worn syncros don't cause this.
The only clutch adjustment is at the master cylinder rod coming out of the master cylinder, a common problem is that the hydraulic hose on the right side of the firewall starts leaking or the clutch slave or master cylinder is leaking. The rear auto adjust function is basically useless, I'm not kidding, it just doesn't work, the rear brakes need to be adjusted manually, this may place an extra demand on the front brakes which can cause them to overheat which will cause rotor warpage so make sure that the rear brakes are in good working order.