2006 Chevy Corvette Clutch Kit - Preemptive Strike

The new Spec flywheel goes in. Torque using GM's step-up sequence and specifications to a final 74 lb-ft, and be sure to use red threadlocker. You'll have to hold the flywheel from turning here, too. Note the yellow paint mark in the bottom right of the flywheel, which we will line up with a corresponding mark on the pressure plate when it's installed. You can substitute an aluminum flywheel in this system to save about 10 pounds in mass, but we took the steel to be more stop-and-go traffic-friendly (though the aluminum version is said to be quite driveable, too).

The Spec clutch system is cleaned and stacked. With the pressure plate laid upside down, the first clutch disc is placed atop it, followed by the intermediate steel plate separating the clutch discs (shown). The second clutch disc then sits atop this plate, and it is this one that contacts the flywheel. Make sure you have both discs in the correct place facing the correct direction (they're unique, and marked).

Proper clutch alignment is even more critical with twin-disc systems than with single-disc clutches. We're using an actual T56 input shaft instead of the provided plastic tool to minimize slop. Making sure to line up the yellow markings, the pressure plate is put in place and the bolts are started using a 6mm Allen wrench. Use threadlocker here, too, and final tighten in stages to 18-20 lb-ft. We should mention that even though Spec says our steel-flywheel clutch system weighs 1 or 2 pounds less overall than the stock assembly, the fact that the discs and pressure plate are smaller in diameter means actual rotational weight savings are more significant.

DTE's Differential Strut kit goes for $379.00, and includes all paraphernalia needed for a bolt-on installation (including 3/8 laser-cut tempered steel brackets and stainless steel adjustable strut rods). As DTE constantly updates its design to fit the latest casting variations of GM diffs and transmissions-changes often occur mid-model-year-exact bracket shape may differ slightly from that shown. Nonetheless, one part number currently fits all years of manual-trans C6s.

First, the four uppermost bolts securing the transmission to the torque tube are removed and discarded. The differential strut transmission brackets then install with the provided bolts and washers, using three washers behind each bolt as a spacer. Be sure to re-install the wiring harness clip onto the upper bolt on the passenger side.

Moving to the differential housing, the diff brackets bolt atop the diff covers on either side using new bolts. As with all bolts in the kit, use some threadlocker compound here. Though DTE instructions made reference to a factory "resonance suppression counterweight" on the driver side of the diff, we apparently didn't have one and so didn't have to go through the process of temporarily removing it. A so-called cross-strut rod ties the two diff brackets together, and is meant to minimize any possible deflection between the two, side-to-side. While attempting to install it, though, we found that the provided bolts could not be inserted through the diff brackets. The holes appeared to be cut to the correct size, but since DTE painted the brackets, there was just enough increased thickness to interfere with bolt insertion. A drill was used to open them up a tad, and the cross-strut rod was then bolted into place (trim to fit, as needed).

The two main strut rods are then assembled with left- and right-handed thread steel-ball Heim joints at each end. Once bolted between the transmission and differential brackets, they are adjusted using a 1/2-inch open end. Twist each rod the specified amount so that it is pulling its Heim joints together, thereby preloading the rods. Putting these rods under tension reduces the separation forces that the upper diff/trans meeting flange must withstand, which reduces the possibility of case fracture, as well as the oft-resulting transmission output shaft failure. Be careful not to go beyond the specified pre-load here, or gear whine and diff damage will result.

Once the main strut rods have been adjusted, the jam nuts at each Heim joint can be tightened and the installation is complete. Later, when reinstalling the transaxle assembly into the car, we found that only minor adjustments to our 3-inch overaxle exhaust pipes were needed to allow them to clear the DTE diff brackets. Though we haven't technically increased the performance of our C6 here, the extra rigidity we've added to our transaxle assembly should help prevent any failures as we continue to add power, test, tune, and otherwise chase Z06 taillamps with our 2006 project car!

With our new clutch system and diff strut bolted in place, we commence vehicle reassembly. A few quick items to note if you're planning to tackle this task yourself: be sure to tape the shift linkage rod to the torque tube to prevent it from getting bound as the driveline/transaxle assembly is being reinstalled. You'll want to torque all suspension bolts and nuts to GM specification. Also, bleed the clutch hydraulics (a gravity-type bleed is Benson's preferred method). And don't forget to (reconnect and) bleed the rear brakes, too! Special thanks to George Benson for his expert assistance with this installation.