Why is it necessary? Clutch fluid degrades when subjected to high heat that accompanies aggressive driving and to water absorption. The sign of bad fluid is a change in its color from clear to dark and murky. At that point, the fluid needs to be cleaned up. If not done, normal operation of the clutch hydraulics will be disrupted under high-demand circumstances. This can provoke incomplete disengagement of the clutch during high-rpm shifts, which often leads to missed shifts that damage the transmission.
A consistent preventive maintenance routine of keeping the clutch fluid fresh and clean will preclude most pedal issues. And if the clutch pedal is already misbehaving badly, cleaning up the fluid should be the first step in remediation and usually resolves the issue.
With that as background, here is the Ranger clutch fluid protocol.
Step 1 Inspect the fluid in the clutch master cylinder reservoir. If it's not clear and clean, move to Step 2.
Step 2 Change the fluid in the clutch master cylinder reservoir.
Draw out the discolored fluid with a syringe, keeping the corrosive fluid off your paint.
Wipe down the reservoir and the rubber fitting on the cap using a clean, lint-free towel.
Refill the reservoir to the fill-line with fresh fluid specified in the owner's manual.
Replace the reservoir cap tightly.
Step 3 Pump the clutch pedal strongly and rapidly 20-30 times. This causes fluid in the hydraulics to flow, blending the new and old fluid, and revealing the color of blended fluid. It also helps to scour crud from the clutch actuator (slave).
Step 4 Inspect the fluid in the reservoir again. If it remains clear and clean, you are finished. If it's not, restart at Step 2.
Inspect the clutch fluid each time you add gasoline or prepare for spirited driving, including the track. If the fluid is not clear and clean, then restart at Step 2.
Even badly degraded, dirty clutch fluid can be substantially cleaned up in 10-15 reservoir changes. That takes less than an hour, costs less than $10 for fluid and a syringe, and doesn't involve a visit to the dealer. I recommend this protocol for every C5 and C6 Corvette with a clutch that sees any form of aggressive driving. If you follow this protocol, you very likely will avoid clutch pedal issues. that is a very important assurance because the car's performance depends on a clutch that is operating properly.
Avoiding driveline breakage at the track
Driver error is the primary cause of breakage among stock Corvettes at the dragstrip. The following are classic mistakes to avoid.
Turning off Active Handling. Doing this provides no straight-line performance benefit whatsoever and denies the driver badly needed help if the rear end gets loose when hitting oil, transmission fluid, antifreeze, or any other slick substance on the track surface. Damage from striking the wall, usually ten feet or less from the side of the car, is normally not covered by a driver's insurance policy.
Failing to reduce rear tire pressure before launching the car. This transfers maximum shock to the driveline, threatening the axles and differential.
Getting the rear wheels hopping on launch or the First-to-Second shift, and then staying on the throttle. This is a great way to break an axle or the differential case.
Performing a burnout with dry rear tires rather than wetting them first in the water box. This torture threatens the axles and differential.
Botching a burnout and redoing it without reapplying water to the rear tires. This can glaze the clutch or break an axle or the differential.
Heating the tires by a burnout and then goosing the throttle repeatedly on the way to the line. This is another great way to break an axle or the differential case.
Brutalizing the transmission with strong missed shifts near redline. This can bend shift forks and damage synchronizers in the transmission.