clutch release problem has me stumped

[don otto]

First let me state I have done at least 100 clutch replacements. I have a 2010 aveo 5 77,000 miles and the clutch started to slip while fully engaged and foot moderately in the pedal. so I bought a aftermarket clutch set from AutoZone and proceeded to replace it. everything went together just like it should. I started it up an the clutch pedal felt weak {very easy to depress). I bleed the system still not much better. The car is very hard to get into gear 1st an 2nd also reverse will grind when attempting to shift into it. Upon further investigation I found the clutch master cylinder leaking out of the rear seal. so I replaced it with one from GM. I bench bleed the new one and bleed the system. ( NO AIR I'M POSTIVE )The slave shows n signs of leaking and the travel of the slave piston rod is 5/8 of an inch. Here is where it gets weird. upon first start up I can shift into all gears fine then I test drive the car and when I try reverse and 1st or 2nd again it will not behave. I'm ready to pull it back apart at this point. I'm scratching my head. it is like the disc is hanging up on the spline.

[josefb134]

Are you fully stopped when trying to shift? I know if you are moving slowly it is hard to put it into 1st gear and if your are moving slightly faster it is hard to put it into 2nd gear. Don't quote me on this but it could be your clutch linkage couldn't it?.. or gear linkage?.. i don't really know what it is called besides linkage lol. I know if i am rolling back or moving forward, i cannot put it into reverse without grinding gears until i fully stop and my RPM's are back down to normal. This is because the 1st through 5th gears are slotted/teethed in a spiral pattern and slip into eachother very easily. But the reverse gear is a straight slotted gear which the teeth/slots have to line up perfectly i order to engage. That could explain part of what is going on.

[don otto]

I did remove the shift linkage and it is a bear to get back into place as I did not mark it. I believe I have it in its proper place. It is weird that when cold (first start up it is fine then 2 minutes into a test drive it acts up)Yes I am fully stopped when trying to ****. I am going to vacuum bleed it today. see if there is any air. tell me is your clutch pedal soft or firm for the entire travel?

[avguy]

.... tell me is your clutch pedal soft or firm for the entire travel?

"soft or firm" are somewhat relative - more important is how it feels now, compared to before the repair. I don't consider mine to be particularly soft or firm, but the only thing I have to compare to is my prior vehicles, and is similar to what I've driven in the past.
But I can say for certain that mine is consistent for the entire pedal travel.
How about the amount and spec of the fluid? The spec for my '05 is GM synthetic #12346190 or equivilent 75W-85 GL-4 gear oil. But naturally it may be a different spec for your 2010.