Clutch repair for a 1992 Sierra will depend on the problem. Clutch systems consist of the clutch, pressure plate and a master and slave cylinder. These parts are not repairable, and the part that has failed will have to be replaced.
The clutch will have to be replaced. The pressure plate could possibly be resurfaced but usually it is as cost effective to replace the pressure plate.
Replace the vent valve. Repair open, short, or resistance problem in the control circuit. Repair an open, or short, or resistance problem in the power circuit, or replace the PCM.
check the back axle oil level first as if it is low the dual power can slip then check the free play on the clutch pedal you should have between 1cm an 2cm of free play in the pedal before you feel pressure on the pedal if there is no free play then adjust the linkage under the cab until you have the desired amount if this is not the problem your clutch is probably gone you will have to split the tractor and examine the clutch and pressure plate and repair as necessary if the clutch is good then you could have a dual power problem so the dual-power unit will have to be checked and repaired
P0740 Torque Converter Clutch Circuit Malfunction The torque converter will need replaced.
Hire a professional mechanic, or buy a repair manual.
It has a leak and is low of refrigerant. Take it to a professional for repair and recharging. Not a DIY job. I had this problem and found that the wiring hooking to the clutch and the pressure switch were broke and intermittently connecting.
$500 for clutch $450-$500 to repair kaH!
If the answer refers to "it's not engaging completely to shift" it could be: * not enough clutch fluid * slave cylinder clutch, damaged and needs bleeding/repair/replacement * master cylinder clutch, damaged and needs bleeding/repair/replacement First check for fluid, if enough, then bleed the circuit changing to new fluid. If looking at the cylinders, any of them is leaking, it needs repair, repair kits are found at NAPA (USA). it's cheaper than replacement, but if the cylinder is damaged it will leak again soon. Some air in the circuit is enough for not letting the clutch work fully, and with the time the fluid will get water from ambient and that water will evaporate (with heat) creating air pockets. If the answer refer to "side pedal play" you need to remove the pedal clutch assembly to replace the bushings
Advanced Clutch seems to be a growing clutch repair shop all over the country. Many local machine shops also repair clutches of different makes and models.
It might be a problem with the "clock spring".
Often a worn clutch disk will not show symptoms when the vehicle has a hydraulic clutch system. The hydraulics "self adjust", leaving the driver surprised when the clutch disk fails altogether. The clutch disk is simple, it is literally pinched between the pressure plate and the flywheel. When the disk wears too thin to fill the space between the pressure plate and the flywheel, there will be nothing for the pressure plate to press against, and there will be no transfer of power between the engine and the transmission. To repair the clutch, the engine and/or transmission must be removed so that you can get to the clutch assembly, which is between the two. It's a significant enough job that you'll need someone to do it for you.