4.8 clutch shudder

[norv struckman]

I have a 2000 short bed single cab chevy pickup with 160,000 miles on it. The clutch pedal started sinking thus loosing clutch disengagement which required double clutching to save the trans synchros. Shortly thereafter the clutch wouldn't slip for a smooth application of power in forward or reverse. Had a local shop replace the throwout (showed wear an loss of thickness) pressure plate and disc and had the flywheel ground, everything through NAPA. Clutch free play is back but it still shudders, so NAPA sprang for new parts on their dime but added a new flywheel. Now the clutch shudders worse than ever! Thinking of taking it to the dealership for original GM parts, as all I can think of is substandard aftermarket parts from NAPA. Advise, thanks, norv.

[Flying Hamster]

Did you get any grease/oil on the disc? Did you clean/degrease the new pressure plate and flywheel? Any chance clutch master cylinder is going bad?

[norv struckman]

I'll check slave movement; maybe the master cylinder is bypassing fluid, thanks, norv.

[68c10airstream]

I was a subaru mechanic for ages and a gmc dealer mechanic for 10 years and oem parts were almost a must years ago. I suspect the same situation today with all of the cheap parts out there. I also went to auto schooling for 2 years and doing clutch work must be clean (as stated above) and a little detail that is missed sometimes as i watch you tube videos is to finger tighten all pressure plate bolts,and now start at say the 12 oclock position and turn 1/2 turn, now go 180 degrees opposite and then tighten the 6 oclock bolt 1/2 turn, now move to the 1 oclock position, and then the 7 oclock position, and continue completely going around numerous times until snug then torque to spec in the criss cross pattern as above.

Also check out your motor mounts for being sloppy as this movement doesn't hold things steady. Good luck.