1981 280zx 2+2. Iwas on the forum a few weeks ago looking for info on a problem having to do with not being able to shift into reverse without grinding and it was hard to shift into 1st. I changed the slave cylinder and master cylinder. Problem is gone for a few days; now it is slowly coming back any answers?

 

Possibly still air in the system, bad hose, or the syncro's are going out?

 

Throw out bearing ?

 

^ I second that. Is it making any kind of noise while in neutral? Also you could have a clutch disk worn also. Happened to me before. Actually it had a couple of the springs broken off. And then it destroyed my throwout bearing. What a mess that was.

 

second on the bleeding. quick and easy.
sometimes you need to rev the motor a bit when shifting into reverse.
It would be a good idea to make sure you have enough oil in the tranny. while you have the car on jacks you might as well change the oil and add a gear oil additive.

 

I always shift into 5th then R on and manual car w/o letting up on the clutch till im in R never ground once for me lol